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FRONTISPIECE. 




Heavf/n, at the Invocation of Genius, bestows on the laborious the 
blessi7jgs of Mechanical and Scientific Inventiom, 

(2) 



THE 

ARTIST'S AND MECHANIC'S 
REPOSITORY, 

AND 

WORKING MAN'S INFORMANT; 

EMBRACING 

CHEMISTRY. ABSTRACTS OF ELECTRICITY, GALVANISM, 

MAGNETISM, MECHANICS, PNEUMATICS, 

OPTICS, AND ASTRONOMY. 

ALSO, 

MECHANICAL EXERCISES 

IN 
IKON, STEEL, LEAD, ZINC, COPPER AND TIN, SOLDERING, 

WITH A 

DESCRIPTION OF THE SLIDE RULE, 

Its Definitions and Examples illustrating every manner of its use, 

which is applicable to every mode of Measurement, 

and to all the Mechanical Powers : 

ALSO, 

A VARIETY OF USEFUL RECEIPTS, 

Extending to every profession and occupation in life, and embracing 

practical subjects ; the major part being original and the remain- 

der selections from the best authorities. In addition to 

which Miscellanies is a valuable Collection of 

Practical Receipts in Dyeing Silk^ 

Woollen, Cotton, and Leather. 



BY JAMES PILKINGTON. 



PHILADELPHIA : 
PUBLISHED BY JAMES PILKINGTON, 

No. 26 NORTH EIGHTH STREET. 






Entered, according to the Act of Congress, in the year 1839, 
BY JAMES PILKINGTON, 

In the clerk's office of the district court of the eastern district of 
Pennsylvania. 

3 ?- 4"^ 



DEDICATION. 



TO THE 

REV. JAMES W. COOKE, 

ASSISTANT MINISTEK OF ST. GEORGE'S CHURCH, 

NEW YORK, 

THE FOLLOWING WORK, 

DESIGNED TO TROMOTE THE tSEFtL ARTS, 
IS RESPECTFULLY INSCRIBED, 

AS A TOKEN OF GRATITUDE AND AFFECTION WHICH I OWE TO HIM A3 

god's instrument in conveying to myself and FAMILY 

THE choicest spiritual BLESSINGS. 

While his sacred profession requires hirn to devote his time 
and talents to the spiritual interests of men, I trust he will not 
regard with indifference my present effort to advance the happiness 
and welfare of mankind. 

Respectfully and affectionately, 

JAMES PILKINGTON. 

(5) 
1* 



PREFACE. 



It has been, and necessarily is, as well the 
object arid desire of all those who have merited, 
but not unexceptionably received, the blessings 
of their fellow men, for their general usefulness, 
and the benefits they have conferred on their 
species, either by their pen or personal exertions, 
as that the events to the production of which 
they have been instrumental, have been of prac- 
tical and general utility ; for the object of all 
study ought to be like the end of all wisdom, 
tending to universal good. 

Upon such a principle has the Editor of this 
Book proceeded. Finding the desideratum in 
the first place (which this Book supplies,) in his 
own condition, he was naturally led to a research 
in scientific works of every kind, as no single 
volume, which is here presented, could aflTord, 
and collecting those things which proved suc- 
cessful in his experiments, he thought it could 
not be otherwise than extremely beneficial to 
publish his compilation. 



V131 PREFACE. 

In fulfilling the duty of preparing it for the 
press, an evident aim to general practical utility 
has constantly been borne in mind. The man 
of family, the artist, the mechanic, the farmer, 
and the labouring man, have all been particularly 
remembered. And in order to render it easy 
of reference to all the interesting subjects upon 
which it treats, and the useful information it em- 
braces, an unusually large and correct Index has 
been inserted, giving every facility that can be 
wished. 

In conclusion, the Editor begs leave to state, 
that neither time nor expense has been consider- 
ed in rendering it in its compilation worthy the 
favour and patronage sohcited for it, claiming no 
merit but that exercise of judgment dictated by 
experience, which is the source of true wisdora 
in. a faithful and select compilation, accompanied 
with a sincere desire to benefit those classes of 
the community to which it is addressed. 



ARTISTS' AND MECHANICS' 
REPOSITORY. 



CHEMISTRY. 



OF CHEMICAL NOMENCLATURE. 

From the revival of learning, after the fall of the Ro- 
man empire, to nearly the close of the seventeenth cen- 
tury, Chemistry was chiefly confined to those who fol- 
lowed it with alchemical views. Those persons, many of 
whom knew that they were deceiving their patrons, 
while others v/ere desirous to conceal their self-delusion, 
or to create admiration by the appearance of having 
done much, were anxious to give every product of their 
laboratories a mysterious, extraordinary, or unintelligible 
name. As they did not act in concert, the same prepa- 
ration obtained very different names ; and, as they were, 
with few exceptions, as eminent for ignorance as effron- 
tery, and carried on their operations at random, they 
examined but superficially the substances which they 
undertook to denominate, and knew not to what they 
were indebted for their leading properties. Such names 
as horn moon, mercury of life, the wonderful salt, the 
salt loith many virtues, form but a small specimen of a 
prodigious number, equally inappropriate and ridiculous. 
Hence, when the dreams of alchemy were broken by the 
dawn of a more enlightened day — when men who had 
the promulgation of truth only for their object, became 
chemists, from a persuasion of the advantages which the 

(9) 

r 



10 CHEMISTRY. 

cultivation of that science would afford to mankind, they 
found it difficult to unravel the confusion which the 
misnomers of their predecessors had created. In propor- 
tion as discoveries were multiplied, the want of a regular 
and appropriate nomenclature increased, and formed a 
strong bar to the general diffusion of a taste for chemical 
researches. A few innovations, which were made by. 
single individuals, in order to accommodate the language 
of chemistry to the improved state of knowledge, served 
only to show how much was still wanted. It is per- 
fectly obvious that names founded upon a mistaken viewi 
of the properties of things, tend to the propagation of 
erroneous opinions, and that, when a vast number of sub- 
stances are designated at random, without any connection; 
in names, although nearly related in composition, the 
mere effort of memory to recollect these names, willi 
exceed the effort which ought to be required for the ac-^ 
quisition of a science. Towards the close of the lastl 
century, therefore, several eminent French chemists- 
determined to take a comprehensive view of the subject, , 
and to remodel the whole system of chemical nomencla- 
ture — a task which they completed in 1797. Their 
object was to reject all the old names which were known 
to convey false ideas, but to preserve those which were 
not of this class, and to which custom had given a cur- 
rency, scarcely and not usefully to be checked. They 
at the same time introduced new terms, of appropriate 
derivation ; and the method of forming compound terms, 
so as to indicate the composition of compound bodies, 
was pointed out. This system of nomenclature possessed 
so much merit, that the adoption of it soon became gene- 
ral in France ; and from thence, it spread with great 
rapidity to other countries, where it was received either 
entirely, or with such improvements as experience war- 
ranted. The objections which have been urged against 
it are futile ; they have chiefly amounted to this, — that 
it is not absolutely perfect, and will, by the progress of 
discovery, hereafter require to be modified. On the con- 
trary, a high eulogium on its value and opportune 



CHEMICAL NOMENCLATURE. 



11 



3stablishment is conveyed by the opinion of several emi- 
nent chemists, that the present state of chemistry could 
not be communicated, much less remembered, by the 
language previously in use. 

The following table will exhibit the most important 
changes of terms which have been made, and more par- 
ticular details will occur, as an account of each sub- 
stance gives occasion : 



Old names. 

Acetous Salts, - - - 
Acid of vitriol, phlogisti 

cated, 

of alum - - - 

of vitriol - - - 

vitriolic - - - 

of sulphur - - 

of nitre, phlogisti- 

cated, 

■ of nitre, dephlogisti- 



JVew names. 
Acetates. 
Sulphurous acid. 



cated, 

— of saltpetre - - 

of sea-salt - - 

marine - - - 

— dephlogisticated ma- 
rine 

aerial - - - - 

— of chalk - - - 

— cretaceous - - 
calcareous - - 

— of charcoal i - 

mephitic - - - 

— - of spar or fluor 

— sparry - - - 

of borax - - - 

of arsenic - - 



•of tungsten 
•of wolfram 
-of molybdina 



^Sulphuric acid. 

J 

Nitrous acid. 

Nitric acid. 

Muriatic acid. 
Oxygenized muriatic acid. 

^Carbonic acid. 

Fluoric acid. 

Boracic acid. 
Arsenic acid. 

Tungstic acid. 

Molybdic acid. 



12 



CHEMISTRY. 



Old 



names. 



Acid of apples - - 

of sugar - - - 

saccharine - - 

of wood sorrel 

of lemons - - 

of cream of tartar 

of benzoin - - 

of galls - - - 

of amber - - - 

of ants - - - 

of cork - - - 

of phosphorus, phlo- 

gisticated - - - 
of phosphorus, de- 

phlogisticated - - 

of silk worms 

of fat - - - - 

sedative - - - 

of lac - - - - 

of milk - - - 

saccholactic - - 

of sugar of milk 



Air, 



dephlogisticated 
empyreal - - - 
vital - - - - 
pure - - - - 
impure or vitiated 
burnt - - - . 
phlogisticated 
inflammable - - 
marine acid - - 
dephlogisticated ma- 
rine acid 



JVew names. 
Malic acid. 

Oxalic acid. 

Citric acid. 
Tartaric acid. 
Benzoic acid. 
Gallic acid. 
Succinic acid. 
Formic acid. 
Suberic acid, i;^ 

Phosphorus acid. 

Phosphoric acid. 

Bombic acid. 
Sebacic acid. 
Boracic acid. 
Laccic acid. 
Lactic acid. 

Mucous acid. 

Gas.* 

>Oxygen gas. 



} Nitrogen gas, or azote, or 
C azotic gas. 

Hydrogen gas. 

Muriatic acid gas. 
) Oxygenized muriatic acid 
) gas. 



* The term gas is now used as a general name for all kinds of 
air, except atmospheric air. 



CHEMICAL NOMENCLATURE. 



13 



Old names. 

Air, hepatic - - - 

— fetid of sulphur - 

— fixed - - - 

— solid, of Hales 

— alkaline - - - 

Algaroth, powder of - 

Alkalies, fixed - - - 
Alkali, volatile - - - 

concrete volatile 

Alkalies, caustic - - 

Alkalies effervescent, or 
not caustic, or aerated, 
or mild. 
Alkali vegetable - - 

mineral - - - 

marine - - - 



Prussian 



Alum I 

Antimony, crude - - 

diaphoretic - J 

Aquafortis - - - - 
Aqua-regia - - - - 
Aqua ammonia pura 
Argil, or argillaceous earth, 

Barilla 

Benzoar mineral - - - 
Black lead - - - - 
Blue, Prussian - - - 

Borax 

Butter of antimony - - 
Calces, metallic - - - 
Caustic, lunar - - - 



JVew names. 
Sulphuretted hydrogen gas. 

Carbonic acid gas. 

Ammoniacal gas. 

White oxide of antimony by 
the muriatic acid. 

Potash and soda. 

Ammonia. 

Carbonate of ammonia. 

Pure alkalies, or those de- 
prived of carbonic acid. 

Alkaline carbonates, or alka- 
lies combined with carbo- 
nic acid. 

Potash.* 

Soda. 

Prussiate of potass. 
Sulphate of alumina and 

potass. 
Sulphuret of antimony. 
White oxide of antimony, 

by the nitric acid. 
Nitric acid of commerce. 
Nitro-muriatic acid. 
Ammonia. 
Alumine. 

Carbonate of soda. 
Oxide of antimony. 
Hyper-carburet of iron. 
Prussiate of iron. 
Borate of soda. 
Muriate of antimony. 
Metallic oxides. 
Fused nitrate of silver. 



* The potash of commerce, when purified, is now called potass. 
2 



14 CHEMISTRY. 

Old names. JVew names. 

Q^Yme \ ^^^^^ ^^^^^ ^^ '^^^ ^Y **i^ 

\ acetous acid. 

Ceruse of antimony - - ^^^^^ .^^/^f. ^^ antimony by 

•^ ( precipitation. 

Chalk - - - - - - Carbonate of lime. 

Charcoal, pine - - - Carbon. 

Cinnabar \ ^^^ sulphuretted oxide of 

\ nnercury. 

Colthothar of vitriol - ^^^ ^^'^f ''^ . j"-*^"' ^^ ^^^ 

( sulphuric acid. 

Copper, acetated - - Acetate of copper. 

Copperas, green - - - Sulphate of iron. 

— — blue - - - of copper. 

Cream of tartar - - - Supertartrate of potass. 

Earth, calcareous - - Lime. 

aluminous - - ) ., 

n , > Alumme. 

of alum - - - ^ 

siliceous - , - - Silex. 

ponderous - - Barytes. 

maenesian - - ? a/t • 

°. .. > Magnesia. 

muriatic - - - ) . ° 

Egg, white o{ - ' ' Albumen. 

Elastic gum - - - - ^ r^ x u 

T I. ^ 1 1 \ Caoutchouc. 

Indian rubber - - - ) 

Emetic tartar - - - j Antimoniated tartrate of 

( potass. 

Essences Volatile oil. 

Ethiops martial - - - Black oxide of iron. 

mineral ' ' ' ) Black sulphuretted oxide of 

per se - - - ) mercury. 

Flowers, metallic - - Sublimated metallic oxides. 

of sulphur - sulphur. 

Fluors Fluates. 

Glass of bismuth - - Vitreous oxide of bismuth. 

Glue or jelly - - - Gelatine. 

Glutinous matter - - Gluten. 

Gypsum Sulphate of lime. 

Hepars ... - - Sulphurets. 



CHEMICAL NOMENCLATURE. 15 

Old names. JVew names. 

Heat, latent, or matter of ) q^i^^i^^ 
heat 5 * 

-, . , ( Red sulphuretted oxide of 

Hermus mineral - - j antimony. 

Lapis infernalis - - - Fused nitrate of silver. 

Leys Solutions of alkalies. 

Liquor gicum^ - - - | Solutions of siliceous potash. 

r, (Litharge, or semi- vitreous 

L^harge " " " " j oxidi of lead. 
Liver of sulphur, alkaline Sulphuret of potash. 
Liver of sulphur, calcareous Sulphuret of lime. 
Luna cornea - - - Muriate of silver. 

T.^ . ^ ^ , . ^, ( Oxide of bismuth by the 

Magistery of bismuth J ^j^^.^^ ^^j^ 

of lead - - Precipitated oxide of lead. 

Magnesia alba^^^ - - | Carbonate of magnesia. 

black - - Black oxide of manganese. 

Masticot Yellow oxide of lead. 

Matter, amylacious - - Fecula, or starch. 

Mephitis Nitrogen. 

Minium Red oxide of lead. 

Mother waters - - - Deliquescent saline residues. 

Spet're" -" -' -' -' j Nitrate of potash. 
Nitres - - - - - Nitrates. 
Oils, fat Fixed oils. 

■ — essential - - - ^ ir i >.! i 
,, I } Volatile oils. 

— ethereal - - - ^ 

— of tartar per deli- ) Solution of carbonate of 

quium 5 potash. 

Phlogiston, an imaginary principle, adopted by Stahl 
and his followers, to account for the phenomena of com- 
bustion. Its existence having never been proved, it has 
no name in modern science.* 

* In general, the works in which it is used, may be understood 
by substituting the term " hydrogen," instead of it ; and by 
** dephlogisticated," understanding free from hydrogen. 



16 CHEMISTRY. 

Old names. JVew names* 

Phosphoric salts - - - Phosphates. 

Plumhago . - - - Hyper-carburet of iron. 

T» . ., ^ -, { Red oxide of mercury by 

Precipitate, red - - J the nitric acid. 

perse - - Red oxide of mercury by fire. 

Principle, astringent - - Gallic acid. 

tanning - - Tannin. 

acidifying - - Oxygen. 

inflammable, identical with Phlogiston. 

Pyrites of copper - - Sulphuret of copper. 

martial - - - > ^ . 

r ,.,. > ot iron. 

factitious - - y 

Reul^ar - - - - - - Red sulphureted oxide ofarsenic. 

Regulus of a metal - The metal in a state of purity. 

Rust of copper - - - - Green oxide of copper. 

— - — of iron - - - - Carbonate of iron. 

SaflTron of mars - - - - Red oxide of iron. 

Sal ammoniac - - - - Muriate of ammonia. 

— polychrest - - - - Sulphate of potass. 

Salt, common or sea - - Muriate of soda. 

-— — febrifuge of Sylicius Muriate of potass. 

a ^^ r '^.^ c • S Phosphate of soda and am- 

fealt, lusible oi urme - < ^ . 

I morna. 

Salt glaubers - - - Sulphate of soda. 

epsom - - - - - of magnesia. 

of Sorel - - - - Super-oxolate of potass. 

of wormwood - - Carbonate of potass. 

vegetable - - - - Tartrate of potass. 

sedative - - - - Boracic acid. 

Sthal's sulphureous - Sulphate of potash. 

Selenite Sulphate of lime. 

Spar, calcareous - - - Crystallized carbonate of lime. 

fluor - - - - - Fluate of lime. 

ponderous - - - Sulphate of barytes. 

Spirit, ardent - - - - Alcohol. 

of nitre - - - - Nitric acid. 

of nitre, fuming - - Nitrous acid. 

of salt Muriatic acid. 

of sal ammoniac - Ammonia. 



CHEMICAL NOMENCLATURE, 17 

Old names. JVew names. 

Spirit of vitriol - - . - Sulphuric acid. 

of wine - - - - Alcohol. 

Spiritus rector - - - - Aroma. 

e I 1- . • i Corrosive muriate of mer- 

oublimate, corrosive - < 

( cury. 

Sugar of lead - - - - Acetate of lead. 

Sulphur, alkaline liver of - Sulphuret of potass, soda, &c. 

, „. 1. r i Alkaline sulphurets contain- 

metallic liver of < . . / 

( ing metals. 

Tartar Super-tartrate of potass. 

,. i Antimoniated tartrate of po- 

emetic - - < . ^ 

I tass. 

vitriolated - - - Sulphate of potash. 

Tartars Tartrates. 

Tinctures, spirituous - - Resins dissolved in alcohol. 

rp , ... . , i Yellow oxide of mercury by 

lurbith mineral - - 7 , . ^ J 

I sulphuric acid. 

Verdigris, or rust of cop-^ 

^ ' ' " J i" it VGreen oxide of copper. 
^exposed to the \ ir 

.air - - - J 

c iu 1 C Acetate of copper mixed 

ol the shops < ... ., ^^ 

A ^ with oxide. 

H^f'll H i Crystallized acetate of cop- 

Vinegar, distilled - - - Acetous acid. 

radical - - - Acetic acid. 

Vitriol, blue or roman - Sulphate of coppen 

green - - - > r • 

^ ,. , > ol iron. 

martial - » - 



white - = - of zinc. 

Vitriols Sulphates. 

Water, acreted or acidu- ( Water impregnated with 
lated. \ carbonic acid. 

h • t' S W^^^^ impregnated \yith 

P \ sulphuretted hydrogen. 

2* 



18 CHEMISTRY. 



CHEMICAL TERMS EXPLAINED. 



To the preceding view of chemical nomenclature, the 
following explanations of terms wdll not perhaps be an 
unacceptable addition. 

Affinity, (a proximity of relationship.) The term af- 
finity is used indifferently with attraction. See Attrac- 
tion, 

Air. This term, till lately, was used as the generic 
name for such invisible and exceedingly rare fluids as 
possess a very high degree of elasticity, and are not con- 
densible into the liquid state by any degree of cold 
hitherto produced; but, as this term is commonly em- 
ployed to signify that compound of aeriform fluids which 
constitutes our atmosphere, it has been deemed advisable 
to restrict it to this signification, and to employ as the 
generic term, the word Gas, for the diflferent kinds of 
air, except what relates to our atmospheric compound. 
The atmosphere may be said, in general terms, to consist 
of oxygen and nitrogen ; but atmospheric air, even when 
purest, always contains a small proportion of other prin- 
ciples. Murray states its exact composition as follows : — 



By measure. 

Nitrogen gas, - 77.5 
Oxygen gas, - 21.0 
Aqueous vapour, 1.42 - 
Carbonic acid gas, .08 - 


By weight. 

- - 75.55 

- - 23.32 
. - 1.03 
. . .10 


100.0 


100.0 



Alchemy. That branch of chemistry which relates 
to the transmutation of metals into gold ; the forming a 
pan9.cea or universal remedy, an alcahest, or universal 



CHEMICAL TERMS EXPLAINED. 19 

menstruum, an universal ferment, and many other absurd- 
ities. 

Alchemist One who practises the mystical art of 
alchemy* 

Alkali^ or ant-acid. Any substance which, when 
mingled with acid, produces fermentation. (See Alkalies.) 

Alloy. 1. Where any precious metal is mixed with 
another of less value, the assayers call the latter the 
alloy, and do not in general consider it in any other point 
of view, than as debasing or diminishing the precious 
metal. 

2. Philosophical chemists have availed themselves of 
this term, to distinguish all metallic compounds in gen- 
eral. Thus brass is called the alloy of copper and zinc ; 
bell-metal, an alloy of copper and tin. 

Every alloy is distinguished by the metal which pre- 
dominates in its composition, or which gives it its value. 
Thus English jewelry, trinkets, are ranked under alloys 
of gold, though most of them deserve to be placed under 
the head of copper. When mercury is one of the com- 
ponent metals, the alloy is called amalgam. Thus w^e 
have an amalgam of gold, silver, tin, &c. Since there 
are about thirty different permanent metals, independent 
of those evanescent ones that constitute the basis of the 
alkalies and earths, there ought to be about 870 differ- 
ent species of binary alloys. But only 132 species have 
been made and examined. Some metals have so little 
affinity for others, that as j^et no compound of them 
has been effected, whatever pains have been taken. 
Most of these obstacles to alloying, arise from the differ- 
ence in fusibility and volatility. Yet a few metals, the 
melting point of which is nearh/ the same, refuse to 
unite. It is obvious that two bodies will not combine, 
unless their affinity or reciprocal attraction be stronger 
than the cohesive attraction of their individual particles. 
To overcome this cohesion of the solid bodies, and ren- 
der affinity predominant, they must be penetrated by 
caloric. If one be very difficult of fusion, and the other 
very volatile, they will not unite unless the reciprocal 



20 CHEMlbTllY. 

attraction be exceedingly strong. But if that degree of 
fusibility be almost the same, they are easily placed in 
the circumstances most favourable for making an alloy. 
If we are, therefore, far from knowing all the binary 
alloys which are possible, we are still further removed 
from knowing all the triple, quadruple, &c. which may 
exist. It must be confessed, moreover, that this depart- 
ment of chemistry has been imperfectly cultivated. 

Analysis, The resolution, by chemistry, of any matter 
into its primary and constituent parts. The processes 
and experiments which chemists have recourse to, are 
very numerous and diversified, yet tliey may be reduced 
to two species, which comprehend the whole art of 
chemistry. The first is, analysis, or decomposition ; the 
second, synthesis, or composition. In analysis, the parts 
of which bodies are composed, are separated from each 
other: thus if we reduce cinnabar, which is composed of 
sulphur ^nd mercury, and exhibit those two bodies in a 
separate state, w^e say we have decomposed or analyzed 
cinnabar. But if, on the contrary, several bodies be 
mixed together, and a new substance be produced, the 
process is then termed chemical composition, or synthesis : 
thus, if by fusion and sublimation, we combine mercury 
with sulphur, and form cinnabar, the operation is termed 
chemical composition, or composition by synthesis. Chem- 
ical analysis consists of a great variety of operations. 
In these operations, the most extensive knowledge of 
such properties of bodies as are already discovered, must 
be applied, in order to produce simplicity of effect and 
certainty in the results. Chemical analysis can hardly 
be executed with success, by one w ho is not in possession 
of a considerable number of simple substances, in a state 
of great purity, many of which, from their effects, are 
called reagents. The word analysis, is often applied by 
chemists to denote that series of operations by which the 
component parts of bodies are determined, w^hether they 
be merely separated or exhibited apart from each other ; 
or whether these distinctive properties be exhibited by 
causing them to enter into a new combination, without 



CHEMICAL TERMS EXPLAINED. 21 

the perceptible intervention of a separate state ; and in 
the chemical examination of bodies, analysis or separa- 
tion can scarcely ever be effected, without synthesis 
taking place at the same time. 

Apparatus, This term is applied to the instruments, 
the preparation, and arrangements, of every thing ne- 
cessary in the performance of any operation, medical, 
surgical, or chemical. 

Jlssay, This operation consists in determining the 
quantity of valuable or precious metal contained in any 
mineral or metallic mixture, by analyzing a small part 
thereof The practical difference between the analysis 
and assay of an ore, consists in this : — The analysis, if 
properly made, determines the nature and qualities of 
all the parts of the compound; whereas, the object of 
the assay consists in ascertaining how much of the par- 
ticular metal in question may be contained in a certain 
determinate quantity of the material under examination. 
Thus, in the assay of gold or silver, the baser metals are 
considered as of no value or consequence ; and the 
problem to be resolved is simply, how much of each is 
contained in the ingot or piece of metal intended to be 
assayed. 

Astringent. That which, when applied to the body, 
renders the solids denser and firmer, by contracting their 
fibres, independently of their Ifving, or muscular power. 
Astringents thus serve to diminish excessive discharges ; 
and by causing greater compression of the nervous fibril- 
lae, may lessen morbid sensibility or irritability. Hence 
they may tend indirectly to restore the strength, when 
impaired by these causes. The chief class of these 
articles are the acids, alum, lime-water, chalk, certain 
preparations of copper, zinc, iron, and lead ; the gallic 
acid, which is commonly found united with the true 
astringent principle, was long mistaken for it. Seguin 
first distinguished them ; and, from the use of this prin- 
ciple in tanning skins, has given it the name of tannin. 
Their characteristic differences are, the gallic acid forms 



22 CHEMISTRY. 

a black precipitate with iron ; the astringent principle 
forms an insoluble compound with albumen. 

Atmosphere, The elastic invisible fluid which sur- 
rounds the earth to an unknown height, and encloses it 
on all sides. (See Air.) 

Atoms. In the chemical combination of bodies with 
each other, it is observed that some unite in all propor- 
tions ; others in all proportions as far as a certain point, 
beyond which combination no longer takes place ^. there 
are also many examples in which bodies unite in one pro- 
portion only, and others in several proportions ; and these 
proportions are definite, and in the intermediate ones no 
combination ensues. And it is remarkable, that when 
one body enters into combination with another, in several 
different proportions, the numbers indicating the greater 
proportions are exact simple multiples of that denoting 
the smallest proportion. In other w^ords, if the smallest 
portion in which B. combines with A. be denoted by 10, 
A. may combine with twice 10 of B. or with three times 
10, and so on ; but with no intermediate quantities. 
Examples of this kind have of late so much increased in 
number, that the law of simple multiples bids fair to 
become universal with respect at least to chemical com- 
pounds, the proportions of which are definite. By the 
term atoms, we are to understand the smallest particles 
of which bodies are composed. An atom, therefore, 
must be mechanically indivisible, and of course a fraction 
of an atom cannot exist, and is a contradiction in terms. 
Whether the atoms of different bodies be of the same 
size, or of different sizes, we have no sufficient evidence. 
The probability is, that the atoms of different bodies are 
of unequal sizes; but it cannot be determined whether 
their sizes bear any regular proportion to their relative 
weights. We are equally ignorant of their shape ; but 
it is probable they are spherical. Sir Isaac Newton 
closes an admirable disquisition on the nature, laws, and 
constitution of matter, by stating the great probability 
that God in the beginning formed matter into solid, mas- 
sive, impenetrable, moveable particles or atoms, of such 



CHEMICAL TERMS EXPLAINED. 23 

sizes and figures, and with such other properties, and in 
such proportion to space, as most conduced to the end 
for which he formed them ; and that these primitive par- 
ticles, being absolute soHds, are incomparably harder 
than any of the bodies compounded of them, even so 
hard as to be incapable of wearing or breaking in pieces, 
nothing but Infinite Power being able to destroy what 
Infinite Power made one in the first creation. That 
nature may be lasting, the changes of corporal things are 
to be attributed only to the various separations and new 
associations of these permanent particles; and when 
compound bodies break, it is not in the midst of solid 
particles, but where these are laid together, and touch 
only in a few points. 

Attraction. The terms attraction, or aflinity, and 
repulsion, in the language of modern philosophers, are 
employed merely as the expression of general facts, that 
the masses or particles of matter have a tendency to 
approach and unite to, or to recede from one another, 
under certain circumstances. The term attraction is 
used synonymously with aflSnity. 

All bodies have a tendency or power to attract each 
other, more or less, and it is this power which is called 
attraction. 

Attraction is mutual : it extends to indefinite distances. 
All bodies, whatever, as well as their component elemen- 
tary particles, are endued with it. It is not annihilated, 
at however great a distance w^e suppose them to be 
placed from each other ; neither does it disappear though 
they be arranged ever so near each other. 

The nature of this reciprocal attraction, or at least 
the cause which produces it, is altogether unknown to 
us. Whether it be inherent in all matter, or whether 
it be the consequence of some other agent, are questions 
beyond the reach of human understanding ; but its exis- 
tence is nevertheless certain. 

The instances of attraction which are exhibited by 
the phenomena around us, are exceedingly numerous, 
and continually presenting themselves to our observation. 



24 CHEMISTRY. 

The effect of gravity, which causes the weight of bodies, 
is so universal, that we can scarcely form an idea how 
the universe could exist without it. Other attractions 
such as those of magnetism and electricity, are likewise 
observable ; and every experiment in chemistry tends to 
show, that bodies are composed of various principles or 
substances, which adhere to each other with various 
degrees of force, and may be separated from each other 
by known methods. 

The species of attraction called chemical attraction^ 
is also not unfrequently designated by the appellation of 
the attraction of composition, or chemical affinity. This 
kind of attraction takes place only between the elemen- 
tary particles of different bodies; and every integrant 
part of the compound which results from its effects, dif- 
fers in its properties from any of its component parts. 
It is by this change of properties that chemical combi- 
nation, or the action of chemical attraction, is distinguish- 
ed from mere mechanical mixture. By mechanical mix- 
ture, it is obvious, that gold, however minutely divided, 
could not exist in every part of a fluid lighter than itself; 
but when the fluid has a chemical attraction for gold, 
the solution is homogeneous, and incapable of separation 
by the filter, or any other mechanical means. 

In order to bring aflSnity fully into action, it is in gen- 
eral necessary that one or both of the bodies presented 
to each other, should be in a fluid state ; or that heat 
should be applied to disunite the particles, by lessening 
the attraction of cohesion; for mechanical subdivision or 
comminution never extending to the separation of the 
ultimate particles of bodies, seldom allows that liberty 
of action, in the exercise of which afiinity appears. 
Instances, however, occur, in which two solids produce a 
fluid : thus, if pounded ice and muriate of soda be mix- 
ed together, a fluid brine will be attained, unless the 
temperature, at the time of the experiment, is lower 
than that at which brine freezes, and this is thirty-eight 
degrees below the freezing point of water. 

Dr. Black discovered that whenever a body changes 



CHEMICAL TERMS EXPLAINED. 25 

its state by chemical affinity, its temperature is changed 
at the same time, either lessened or increased. 

The discoveries of Sir H. Davy, seem to establish as 
a fact, that no chemical affinity takes place between the 
particles of bodies, unless they be in an opposite electri- 
cal state ; and that by artificially changing the electrical 
state of bodies, their affinities may be modified or 
destroyed. 

The action of the affinity of composition, in different 
cases, has been distinguished in the following manner : 

1. When two principles, united together, are sepa- 
rated by means of a third, we are said to have an ex- 
ample of simple affinity. This simple affinity, Bergman 
called simple elective attraction, an expression still much 
used by chemists. 

2. When a body, composed of two others, cannot be 
destroyed by a third or fourth body separately applied, 
yet is destroyed or decompounded by the action of a 
third and fourth bodies, if these be united before they 
are added to it ; the example in this case, and when any 
greater number of bodies are employed, is called com- 
pound affinity, or compound elective attraction, 

3. When two bodies which have no perceptible action 
on each other, unite by the addition of a third body, the 
example is called intermediate affinity. It is instanced 
in the union of oil and water, by the means of an alkali. 

Tables of elective attraction have been constructed, 
which are of singular service in directing the attention 
of the chemist to the effects of substances on each other : 
w^e shall advert to them when w^e have considered the 
properties of substances themselves. 

Bases, This term is usually applied to alkalies, earths, 
and metallic oxides, in their relations to the acids and 
salts. It is sometimes also applied to the particular con- 
stituents of an acid or oxide, on the supposition that the 
substance combined with the oxygen, &c. is the basis of 
the compound to which it owes its particular qualities. 
This notion seems unphilosophical, as these qualities de- 
3 



26 CHEMISTRY. 

pend as much on the state of combination as on the na- 
ture of the constituent. 

Bi. This term is used in anatomy, botany, and chem- 
istry : in composition, it signifies twice or double. 

Calcareoiis, Substances which partake somewhat of 
the nature and quahties of calx. 

Calcination, The fixed residues of such matters as 
have undergone combustion are called cinders, in com- 
mon language, and calxes, but now more commonly ox- 
ides, by chemists ; and the operation, when considered 
with regard to these residues, is termed calcination. In 
this general way, it has likewise been applied to bodies 
not really combustible, but only deprived of some of 
their principles by heat. Thus we hear of the calcina- 
tion of chalk, to convert it into lime by driving oflF the 
carbonic acid and water; of gypsum, or plaster-stone, 
of alum, of borax, and other saline bodies, by which 
they are deprived of their water of crystallization ; of 
bones, which lose their volatile parts by this treatment, 
and of various other bodies. It is also applied to metals, 
in their combination with oxygen, by means of heat. 

Caloric. That which produces the sensation of heat. 
(See Caloric) 

Carburet, A combination of charcoal with any other 
substance : thus carburetted hydrogen is hydrogen hold- 
ing carbon in solution ; carburetted iron is steel, &c. 

Caustic, (To burn ; because it always causes a burn- 
ing sensation.) A substance which alwa5^s causes a burn- 
ing sensation, and has so strong a tendency to combine 
with organized substances, as to destroy their texture. 

Caivk, A term by which the miners distinguish the 
opaque specimens of sulphate of barytes. 

Cementation, A process in which a body in a solid 
state, is surrounded by another in powder, and exposed 
for some time in a close vessel to a degree of heat which 
will not fuse either of the bodies. Iron thus surrounded 
by charcoal is converted into steel ; and copper, by ce- 
mentation v^ith calamine and charcoal, is converted into 



CHEMICAL TERMS EXPLAIMED. 27 

brass; green bottle-glass is converted into porcelcdn by 
cementation with sand, &c. 

Chlorate, A compound of chloric acid with a salifiable 
basis. ^. 

Coagulation, The separation of the coagulable par- 
ticles, contained in any fluid, from the more thin and not 
coagulable particles : thus^ when milk curdles, the co- 
agulable particles form the curd; and when acids are 
thrown into any fluid containing coagulable particles, 
they form what is called coagulum. 

Combination, The intimate union of the particles of 
different substances by chemical attraction, so as to form 
a compound possessed of new and peculiar properties. 

Combustion. The union of a body with oxygen ac- 
companied by the evolution of light and heat ; therefore 
every body which is capable of forming this union, is 
called a combustible. (See Combustion,) 

Compound, The result or effect of a composition of 
different things ; or that which arises from them. It 
stands opposed to simple. 

Concentration. A process by which the watery part 
of any fluid is separated, by evaporation ; or the volatil- 
izing of part of the water of fluids, in order to improve 
their strength. The matter, therefore, to be concen- 
trated, must be of superior fixity to water. This opera- 
tion is performed on some acids, particularly the sulphu- 
ric and phosphoric. It is also employed in solutions of 
alkalies and neutral salts. 

Concretion, The condensation of any fluid substance 
into a more solid consistence. 

The growing together of parts which, in a natural 
state, are separate. 

Condensation. The thickening of any fluid. 

Congelation, The change of liquid bodies, which 
takes place when they pass to a solid state, by losing 
the caloric which kept them in a fluid state. 

Crystallization, A property by which crystal lizable 
bodies tend to assume a regular form, when placed favour- 
able to that particular disposition of their particles. Al- 



28 CHEMISTRY. 

most all minerals possess this property, but it is most 
eminent in saline substances. The circumstances which 
^re favourable to crystallization of salts, and without 
which it cannot take place, are two : 1. Their particles 
must be divided and separated by a fluid, in order that 
the corresponding faces of those particles may meet and 
unite. 2. In order that this union may take place, the 
fluid which separates the integrant parts of the salt must 
be gradually carried off, so that it may no longer divide 
them. (See Crystallization,) 

Cupellation. The purifying of perfect metals by 
means of an addition of lead, which, at a due heat, 
becomes vitrified, and promotes the vitrification and cal- 
cination of such imperfect metals as may be in the mix- 
ture, so that these last are carried otF in the fusible 
glass that is formed, and the perfect metals are left 
nearly pure. The name of this operation is taken from 
the vessels made use of, which are called cupels. 

Decantation. The separation of a fluid fronri -the un- 
dissolved particles or solids which it contains. This is 
done by leaving the fluid at rest in a conical vessel ; and 
when the foreign matter has deposited itself at the bot- 
tom, the fluid is gently poured off, in order not to disturb 
the sediment. When the matter deposited is light, and 
apt to mix with the fluid, or when the vessel containing 
it cannot be conveniently moved, a siphon is employed to 
draw it off A thick woollen thread steeped in the 
liquor, and inclining over the edge of the vessel, makes 
a very good siphon for this purpose. 

Decoction, A fluid holding in solution some substance 
which it has obtained by boiling : thus w^e say a decoc- 
tion of bark, &c. When the preparation is made by 
cold water, it is called an infusion. 

Decomposition. The substances of which any com- 
pound body is formed, are called its component or con- 
stituent parts ; and when these are separated from each 
other, the body is said to be decomposed, or to have 
undergone decomposition. Thus soap is compounded of 
oil and an alkali ; and when the oil and alkaU are sepa- 
rated from each other, the soap is decomposed. 



CHEMICAL TERPrlS EXPLAINED. 29 

Decrepitation, The small and successive explosions 
which take place in many chemical operations, as when 
salts are exposed to heat. 

Deflagration, A chemical term, chiefly employed to 
express the burning or setting fire to any substance ; as 
uitre, sulphur, &c. 

Deplegmation, The operation of rectifying or freeing 
spirits from their watery parts, or any method by which 
bodies are deprived of their water. 

DepJilogisticated. A term of the old chemistry, im- 
plying, deprived of phlogiston, or the inflammable prin- 
ciple. 

Deliquescence, The state of a salt which becomes 
fluid by its absorption of moisture from the atmosphere. 

Desiccation, (Drying.) The expelling or evaporating 
of humid matter from any substance, by means of heat. 

Descensus, Chemists call this a distillation by descent, 
when the fire is at the top and round the vessel, the ori- 
fice of which is at the bottom. 

Detonation, An explosion caused by a sudden expan- 
sion and combustion of certain substances ; it differs from 
decrepitation in being more rapid, and louder. 

Digestion, The slow action of a solvent upon any sub- 
stance, whether assisted by heat or not. 

Distillation, The separation by heat of a volatile fluid 
from other substances which are fixed ; or the separation 
of substances more or less volatile from each other. (See 
Distillation,) 

Ductility, A property by which bodies are elongated 
by repeated or continued pressure. It is peculiar to 
metals. Most authors confound the words malleability, 
laminability, and ductility, together, and use them in a 
loose indiscriminate way ; but they are very different. 
Malleability is the property of a body which enlarges 
one or two of its three dimensions by a blow or pressure 
very suddenly applied. Laminability belongs to bodies 
extensible in dimension by a gradually applied pressure ; 
and ductihty is properly to be attributed to such bodies 
as can be rendered longer and thinner by drawing them 
3* 



30 CHEMISTRY. 

through a hole of less area than the transverse section 
of the body so drawn. 

Ebullition. This consists in the change which a fluid 
undergoes from a state of liquidity to that of an elastic 
fluid, in consequence of the application of heat, which 
dilates and converts it into vapour. 

Effervescence, The bubbling and noise produced by 
the escape of volatile parts from a fluid, or the agitation 
which is produced by mixing substances tc^ether, which 
cause the evolution of a gas. 

Efflorescence. That which takes place when bodies 
spontaneously become converted into a dry powder. It 
is almost always occasioned by the loss of the water of 
crvstallization in saline bodies. 

Elastic. Having the power of returning to the form 
from w^hich it has been forced to deviate, or from which 
it is withheld ; thus a blade of steel is said to be elastic^ 
because if it is bent to a certain degree, and then let go, 
it will of itself return to its former situation ; the same 
will happen to the branch of a tree, a piece of Indian 
rubber, &c. 

Eliquation' An operation in which a substance is 
separated from another which is less fusible, by the 
application of a degree of heat which will fuse only the 
former; thus copper may be separated from its alloj'- 
with lead, with a degree of heat which is sufficient only 
to melt the lead. 

Equivalents. A term introduced into chemistry by 
Dr. Wollaston^ to express the system of definite ratios, in 
which the corpuscular objects of this science reciprocally 
unite. 

Essence. Several of the volatile or essential oils are 
called by this name. 

Ethereal. A term applied to any highly rectified or 
essential oil, or spirit. 

Evaporation. A chemical process usually performed 
by applying heat to any compound substance, in order 
to dispel the volatile parts. It differs from distillation in 
its object, which chiefly consists in preserving the more 



CHEMICAL TERMS EXPLAINED. 31 

fixed matters, while the volatile substances are dissipated 
and lost. And the vessels are accordingly different: 
evaporation being nnade in open shallow vessels, and 
distillation in an apparatus nearly closed from the exter- 
nal air. 

The decree of heat must be duly regulated in evapo- 
ration. When the fixed and more volatile parts do not 
differ greatly in their tendency to fly off, the heat must 
be very carefully adjusted ; but in other cases this is less 
necessary. As evaporation consists in the assumption of 
the elastic form, its rapidity will be in proportion to the 
degree of heat, and the diminution of the pressure of 
the atmosphere. 

Extract The solid matter obtained by evaporating 
the watery parts of a decoction or infusion. 

Fermentation. A slow motion of the intestine par- 
ticles of a mixed body. 

Filtration. An operation by which a fluid is mechan- 
ically separated from consistent particles mixed with it. 
It does not differ from straining. 

An apparatus fitted for this purpose is called a filter. 
The form of this is various, according to the intention of 
the operator. A piece of tow, or wool, or cotton, stuffed 
into the pipe of a funnel, will prevent the passage of 
grosser particles, and by that means render the fluid 
clearer which comes through. Sponge is still more 
effectual. A strip of linen rag wetted and hung over 
the side of the vessel containing the fluid, in such a 
manner that one end of the rag may be immersed in the 
fluid, and the other end may remain without, below the 
surface, will act as a siphon, and carry over the clearer 
portion. Linen or woollen stulis may either be fastened 
over the mouths of proper vessels, or fixed to a frame, 
like a sieve, for the purpose of filtering. All these are 
more commonly used by cooks and apothecaries than by 
philosophical chemists, who, for the most part, use the 
paper called cap paper, made up without size. 

As the filtration of considerable quantities of fluid 
could not be effected at once without breaking the pa- 



32 CHEMISTRY. 

per, it is found requisite to use a linen cloth, upon which 
the paper is applied and supported. 

Precipitates and other pulverulent matters are col- 
lected more speedily by filtration than by subsidence. 
But there are many chemists who disclaim the use of 
this method, and avail themselves of the latter only, 
which is certainly more accurate, and liable to no objec- 
tion, where the powders are such as will admit of edul- 
coration and drying in the open air. 

Some fluids, as turbid water, may be purified by filter- 
ing through sand. A large earthen funnel, or stone bot- 
tle with the bottom beaten out, may have its neck loosely 
stopped with small stones, over which smaller may be 
placed, supporting layers of gravel increasing in fine- 
ness, and lastly covered with a few inches of fine sand, 
all thoroughly cleaned by washing. This apparatus is 
superior to a filtering-stone, as it will clean water in 
large quantities, and may be readily renewed when the 
passage is obstructed, by taking out and washing the 
upper stratum of sand. 

A filter for corrosive liquors may be constructed, on 
the sanfie principles, of broken and pounded glass. {Ures 
Chem, Diet) 

Fixed. An epithet descriptive of such bodies as so far 
resist the action of heat as not to rise in vapour. It is 
the opposite of volatile ; but it must be observed, that 
the fixity of bodies is merely a relative term, as an ade- 
quate degree of heat will dissipate all. 

Fluate. A compound of the fluoric acid with salifiable 
bases : thus, fluate of lime, &c. 

Fluid. A fluid is that, the particles of which so little 
attract each other, that when poured out, it drops, and 
adapts itself in every respect to the form of the vessel 
containing it. (See Fluid,) 

Flux, A general term made use of to denote any sub- 
stance or mixture added to assist the fusion of metals. 

Fluxion, A term mostly applied to signify the change 
of metals, or other bodies, from the solid into a fluid 
state, by the ap'^llcation of heat. (See Fusion.) 



CHEMICAL TERMS EXPLAINED. 33 

Fulmination. A still more violent and sudden explo- 
sion than detonation. 

Fusion. A chemical process, by which bodies are 
made to pass from a solid to a fluid state by means of 
the application of heat. The chief objects susceptible 
of this operation are salts, sulphur, and metals. Salts 
are liable to two kinds of fusion : the one, which is pe- 
culiar to saline matters, is owing to water contained in 
them, and is called aqueous fusion ; the other, w^hich 
arises from the heat alone, is known by the name of 
igneous fusion. 

Gas, Elastic fluid ; aeriform fluid. This term is ap- 
plied to all permanently elastic fluids, simple or com- 
pound, except the atmosphere, to which the term air is 
appropriated. (See Gas,) 

Ide, This terminal is aflixed to oxygen, chlorine, and 
iodine, when they enter into combination with each 
other, or w^th simple combustibles or metals, in propor- 
tions not forming an acid ; thus ox-ide of chlorine, ox-ide 
of nitrogen, chlor-ide of sulphur, iod-ide of iron. 

Incineration. The burning of vegetable or animal 
substances, to obtain their ashes, or fixed residue, which 
is lixiviated. 

Inflammable, Chemists distinguish by this term such 
substances as burn with facility, and flame in an increased 
temperature. 

Infusion. A process that consists in pouring water 
of any required degree of temperature on such sub- 
stances as have a loose texture ; as thin bark, wood in 
shavings or small pieces, leaves, flowers, &c., and suffer- 
ing it to stand a certain time. The liquor obtained by 
the above process is called an infusion. 

lodate. A compound of iodine with oxygen, and a 
metallic basis. 

Iodide. A compound of iodine with a metal ; as Iodide 
of pot-assium. 

Lacquer. A solution of lac in alcohol. 

Lactate. A definite compound formed by the union 
of the acid of whey, or lactic acid, with salifiable bases ; 
thus, lactate of potassa, &c. 



34 CHEMISTRY. 

Levigatlon. The reduction of a hard substance, by 
triture, to an impalpable powder. 

Liquefaction. A term sometimes used synonymously 
with fusion, in others with the word deliquescence, and 
in others with the word solution, 

Lixiviation, The application of water to the fixed 
residues of bodies, for the purpose of extracting the 
saline parts, which dissolve in the water, and afterwards 
crystallize on evaporation. 

Maceration. This term implies an infusion either with 
or without heat, wherein the ingredients are intended to 
be almost wholly dissolved in order to extract their 
virtues. 

Magistery. An obsolete term used by ancient chem- 
ists to signify a peculiar and secret method of preparing 
any medicine, as it were by a masterly process. The 
term was also long applied to all precipitates. 

Martial, Sometimes used to express preparations of 
iron, or such as are impregnated therewith ; as the mar- 
tial regulus of antimony, &c. 

Menstruum, All liquors are so called w^hich are used 
as dissolvents, or to extract the virtues of ingredients by 
infusion, decoction, &c. 

Mineralize, Metallic substances are said to be min- 
eralized when deprived of their usual properties by com- 
bination with some other substance. 

Mother-water, When sea-water, or any other selec- 
tion containing various salts, is evaporated, and the crys- 
tals taken out, there always remains a fluid containing 
deliquescent salts, and the impurities, if present. This 
is called the mother-water. 

Neutral, A term applied to saline compounds of an 
acid and an alkali, which are so called, because they do 
not possess the characters of acid or alkaline salts ; such 
are Epsom-salts, nitre, and all the compounds of alkalies 
with acids. 

Neutralization, When acid and alkaline matter are 
combined in such proportions, that the compound does 
not change the colour of litmus or violets, they are said 
to be neutralized. 



CHEMICAL TERMS EXPLAINED. 35 

Oxidation, The process of converting metals and 
other substances into oxides, by combining with them a 
certain portion of oxygen. It differs from acidification 
in the addition of oxygen not being sufficient to form an 
acid with the substance oxidized. 

Oxide, A substance combined with oxygen without 
being in the state of an acid. Many substances are sus- 
ceptible of several stages of oxidizement, on which ac- 
count chemists have employed various terms to express 
the characteristic distinctions of the several oxides. The 
specific name is often derived from some external char- 
acter, chiefly the colour; thus we have the black and 
red oxides of iron, and of mercury ; the white oxide of 
zinc : but in most instances the denominations proposed 
by Dr. Thompson are adopted. When there are several 
oxides of the same substance, he proposes the terms 
protoxide, deutoxide, tritoxide, signifying the first, second, 
and third stage of oxidizement. Or if two oxides only 
are known, he proposes the appellation of protoxide for 
that at the minimum, and of peroxide for that at the 
maximum, of oxidation. The compounds of oxides and 
water in which the water exists in a condensed state, 
are termed hydrates, or hydroxures. 

Oxygenation, This word is often used instead of oxida- 
tion, and frequently confounded with it ; but it differs in 
being of more general import, as every union with oxy- 
gen, whatever the product may be, is an oxygenation ; 
but oxidation takes place only when an oxide is formed, 

Oxyiode. A term applied by Sir H. Davy to the triple 
compounds of oxygen, iodine, and the metallic bases. 
Lussac calls them iodates. 

Petrifactions, Stouj matters deposited either in the 
w^ay of incrustation, or within the cavities of organized 
substances, are called petrifactions. Calcareous earth 
being universally diffused, and capable of solution in 
water, either alone or by the medium of carbonic acid 
or sulphuric acid, which are likewise very abundant, is 
deposited whenever the water or the acid becomes dissi- 
pated. In this way we have incrustations of limestone 



36 CHEMISTRY. 

or of selenite in the form of stalactites or dropstones, 
from the roofs of caverns, and in various other situations. 
The most remarkable observations relative to petri- 
factions are thus given by Kerwan : 

1. That those of shells are found on, or near, the sur- 
face of the earth ; those of fish, deeper ; those of wood, 
deepest. Shells in specie are found in immense quanti- 
ties at considerable depths. 

2. That those organic substances that resist putrefac- 
tion most, are frequently found petrified; such as shells, 
and the harder species of woods : on the contrary, those 
that are aptest to putrefy are rarely found petrified; 
as softer parts of animals, fish, &c. 

3. That they are most found in strata of marl, chalk, 
limestone, or clay, seldom in sandstone, still more rarely 
in gypsum ; but never in gneiss, granite, basalts, or 
shale; but they sometimes occur in pyrites, and ores of 
iron, copper, and silver, and almost always consist of that 
species of earth, stone, or other mineral that surrounds 
them, sometimes of silex, agate, or cornelian. 

4. That they are found in climates where their ori- 
ginals could not have existed. 

5. That those found in slate or clay are compressed 
and flattened. 

Phlegm, In chemistry this term means the water from 
distillation. 

Phlogiston. The supposed general inflammable prin- 
ciple of Stahl, who imagined it w^as pure fire, or the 
matter of fire fixed in combustible bodies, in order to dis- 
tinguish it from fire in action, or in a state of liberty. 

Phosphate, A salt formed by the union of phosphoric 
acid with salifiable bases ; thus, phosphate of ammonia^ 
phosphate of lime, &c. r«r 

Precipitation, When two bodies are united, for in- 
stance, an acid and an oxide, and a third body is added, 
such as an alkali, which has a greater affinity with the 
acid than the metallic oxide has, the consequence is, 
that the alkali combines with the acid, and the oxide 
thus deserted, appears in a separate state, at the bottom 



CHEMICAL TERMS EXPLAINED. 37 

of the vessel in which the operation is performed. This 
decomposition is commonly known by the name of pre- 
cipitation, and the substance that sinks is named a pre- 
cipitate. The substance, by the addition of which the 
phenomenon is produced, is denominated the precipitant. 

Principles. Substances or particles, which are com- 
posed of twa or more elements ; thus water, gelatine, 
sugar, fibrine, &c., are the principles of many bodies. 
These principles are composed of elementary bodies, as 
oxygen, hydrogen, azote, &c., which are undecomposable. 

Putrefaction. (To become rotten, to dissolve.) Pu- 
trid fermentation. The spontaneous decomposition of 
animal and vegetable matters, that exhale a foetid smell. 
The solid and the fluid matters are resolved into gaseous 
compounds and vapours, which escape and unite an 
earthy residuum. The requisites to this process are : — 
1. A certain degree of humidity. 2. The access of 
atmospheric air. 3. A certain degree of heat. Hence 
the abstraction of the air and water, or humidity, by 
drying, or its fixation by cold, by salt, sugar, spices, &c., 
will counteract the process of putrefaction, and favour 
the preservation of food, on which principle some patents 
have been obtained. 

Pyrites. (So called because it strikes fire with steel.) 
Native compounds of metal with sulphur. 

Radical. This term is applied to that which is con- 
sidered as constituting the distinguishing part of an acid, 
by its union with the acidifying principle or oxygen, 
which is common to all acids. Thus sulphur is the rad- 
ical of sulphuric and sulphurous acids. It is sometimes 
called the base of the acid ; but base is a term of more 
extensive application. 

Rancidity. The change which oils undergo by ex- 
posure to air, w^hich is probably an eflfect analogous to 
the oxidation of metals. 

Reagent — Test. A substance used in chemistry to 

detect the presence of other bodies. In the application 

of tests, there are two circumstances to attend to : viz. 

to avoid deceitful appearances, and to have good tests. 

4 



38 CHEMISTRY. 

The principal tests are the following : 

1. Litmus. The purple of lilnrius is turned to red by 
every acid ; so that this is the test generally made use 
of to detect the excess of acid in every fluid. It may be 
used either by dipping into the water a piece of paper 
stained with litmus, or by adding a drop of the tincture 
to the water to be examined, and comparing its hue with 
that of an equal quantity of the tincture in distilled 
water. 

Litmus already reddened by an acid, will have its pur- 
pie restored by an alkali ; and thus it may also be used 
as a test for alkalies, but it is m.uch less active than 
other direct alkaline tests. 

2. Red cahhage has been found by Watt to furnish as 
delicate a test for acids as litmus, and to be still more 
sensible for alkalies. The natural colour of an infusion 
of this plant is blue, which is changed to a red by acids, 
and to a green by alkalies in very minute quantities. 

3. Brazil loood. When chips of this wood are infused 
in warm water, they yield a red liquor, which readily 
turns blue by alkalies, either caustic or carbonated. It 
is also rendered blue by the carbonated earths held in 
solution by carbonic acid, so that it is not an unequivocal 
test of alkalies till the earthy carbonates have been pre- 
cipitated by boiling. Acids change to yellow the natural 
red of Brazil wood, and restore the red when changed 
by alkalies. 

4. Violets. The delicate blue of the common scented 
violet is readily changed to green by alkalies, and this 
affords a delicate test for these substances. Syrup of 
violets is generally used as it is at hand, being used in 
medicine. But a tincture of this flower will answer as 
well. 

5. Turmeric, This is a very delicate test for alkalies, 
and on the whole, perhaps, is the best. The natural 
colour, either in watery or spirituous infusion, is yellow, 
which is changed to a brick or orange red by alkalies, 
caustic or carbonated, but not by carbonated earths, on 
which account it is preferable to Brazil wood. The pure 



CHEMICAL TERMS EXPLAINED. 39 

earths, such as lime and barytes, produce the same 
change. 

6. Rhubarb. Infusion or tincture of rhubarb under- 
goes a similar change with turmeric, and is equally deli- 
cate. 

7. Sulphuric acid, A drop or two of concentrated 
sulphuric acid, added to water that contains carbonic 
acid, free or in combination, causes the latter to escape 
with a pretty brisk etTervescence, whereby the presence 
of this gaseous acid may be detected. 

8. Nitric and oxTjmuriatic acid, A peculiar use 
attends the use of these acids in the sulphuretted waters, 
as the jsulphuretted hydrogen is decomposed by them, its 
hydrogen absorbed, and the sulphur separated in its natu- 
ral form. 

9. Oxalic acid and oxalate of ammonia. These are 
the most delicate tests for lime and all soluble calcareous 
salts. Oxalate of lime, though nearly insoluble in water, 
dissolves in a moderate quantity in its own or any other 
acid, and hence in analysis oxalate of ammonia is often 
preferred, as no access of this salt can redissolve the pre- 
cipitated oxalate of lime. On the other hand^ the am- 
monia should not exceed, otherwise it might give a false 
indication. 

10. Gallic acid and tinctui^e of galls. These are 
tests of iron. Where the iron is in very minute quan- 
tities, and the water somewhat acidulous, these tests do 
not always produce a precipitate, but only a slight red- 
dening, but their action is much heightened by previously 
adding a few drops of any alkaline solution. 

11. Prussiate of potassa or lime. The presence of 
iron in water is indicated by these prussiates causing a 
blue precipitate : and if the prussiate of potassa is prop- 
erly prepared, it will only be precipitated by a metallic 
salt, so that manganese and copper will also be detected, 
the former giving a white precipitate, the latter a red 
precipitate. 

12. Lime-water, is the common test for carbonic acid ; 
it decomposes all the magnesian salts, and likewise the 



40 CHEMIBTKY. 

aluminous salts ; it likewise produces a cloudiness with 
most of the sulphates, owing to the formation of selenite. 

13. Atmnonia, This alkali when perfectly caustic, 
serves as a distinction between the salts of lime and those 
of magnesia, as it precipitates the earth from the latter 
salts, but not from the former. There are two sources 
of error to be obviated, one is that of carbonic acid 
being present in the water, the other is the presence of 
aluminous salts. 

14. Carbonated alkalies. These are used to precipi- 
tate all the earths ; where carbonate of potassa is used, 
particular care should be taken of its purity, as it gen- 
erally contains silex. 

15. Muriated alumine. This test is proposed by Mr, 
Kirwan, to detect carbonate of magnesia, which cannot, 
like carbonated lime, be separated by ebullition, but 
remains till the whole liquid is evaporated. 

16. Barytic salts. The nitrate, muriate, and acetate 
of barytes are all equally good tests of sulphuric acid in 
any combination. 

17. Salts of silver. The salts of silver are the most 
delicate tests of muriatic acid, in any combination, pro- 
ducing the precipitated luna cornea. All the salts of 
silver likewise give a dark brown precipitate wuth sul- 
phurated waters, which is as delicate a test as any we 
possess. 

18. Salts of lead. The nitrate and acetate of lead 
are the salts of this metal employed as tests. They will 
indicate the sulphuric, muriatic, and boracic acids, and 
sulphuretted hydrogen or sulphuret of potassa. 

19. Soap. A solution of soap in distilled w^ater, or in 
alcohol, is curdled by water containing any earthy or 
metallic salt. 

20. Tartaric acid. This acid is of use in distinguish- 
ing the salts of potassa (with which it forms a precipitate 
of cream of tartar,) from those of soda, from which it 
does not precipitate. The potassa, however, must exist 
in some quantity to be detected by the test. 

21. JVitromuriate of platiitm. This sort is still more 



CHEMICAL TERMS EXPLAINED. 41 

discriminative between potassa and the other alkahes, 
than acid of tartar, and will produce a precipitate with 
a very weak solution of any salt with potassa. 

22. Alcohol, This most useful reagent is applicable 
in a variety of ways in analysis. As it dissolves some 
substances found in fluids, and leaves others untouched, 
it is a means of separating them into two classes, which 
saves considerable trouble in the further investigation. 
Those salts which it does not dissolve, it precipitates 
from their watery solution, but more or less completely 
according to the salt contained, and the strength of the 
alcohol; and as a precipitant it also assists in many 
decompositions. 

Rectification.. (To make clean.) A second distilla- 
tion, in which substances are purified by their more 
volatile parts being raised by heat carefully managed ; 
thus, spirits of wine, ether, &c., are rectified by their 
separation from the less volatile and foreign matter 
which altered or debased their properties. 

Reduction, When a metal is converted into an oxide 
by its combining with oxygen, it loses its metallic prop- 
erties, and assumes the appearance of an earth; but 
when the oxygen with which it is combined is taken from 
it, all its properties as a metal are recovered ; in this 
case the metal is said to be reduced, and the operation 
by which it is eifected is called reduction. Revivifica- 
tion is a v.'ord used in the same sense as reduction, but 
is most commonly employed wheijp mercury is the metal 
used. 

Residuum, is that part of a body which remains after 
the most valuable parts have been separated by com- 
bustion, distillation, or sublimation. 

Roasting, a preliminary operation, which prepares 
mineral substances for undergoing a series of succeeding 
ones, dividing their constituent particles, volatilizing some 
of their principles, and thus, in a certain degree, altering 
their nature. Ores are exposed to this process, with a 
view to separate the sulphur and the arsenic which 
they contain, and to diminish the cohesion of their par- 
4 # 



42 CHEMISTRY. 

tides. CapsuIetJ of earth or iron, crucibles, and roasting 
pots, are the vessels in ^vhich it is usually performed ; 
and the ore is generally exposed to the access of exter- 
nal air. Sometimes, however, the operation is performed 
in close vessels ; and two crucibles, luted mouth to 
moutl), may be employed on such occasions. Roasting 
is synonymous with torefactiou and ustulation, 

Sal. (See Saline.) 

Salifiable, Having the property of forming a salt. 
The alkalies, and those earths and metallic oxides which 
have the power of neutralizing acidity, entirely or in 
part, and producing salts, are called salitiable bases. 

Saline. (From sal, salt.) Of a salt nature. The 
number of saline substances is very considerable ; and 
they possess peculiar characters by which they are dis- 
tinguished from other substances. These characters are 
founded on certain properties, which, it must be con- 
fessed, are not accurately distinctive of their true nature. 
All such substances^ however, as possess several of the 
four following properties, are considered as saline: — 
1. A strong tendency to combination, or a very strong 
affinity of composition. 2. A greater or lesser degree 
of sapidity. S. A grea,teF or lesser degree of solubility 
in water. 4. Perfect incombustibility. 

Saturation. Most bodies which have a chemical 
affinity for each other, will only unite in certain propoi- 
tions. When, therefore, a fluid has dissolved as much 
of any substance as itis capable of dissolving, it is said 
to have reached the point of saturation. Thus water 
will dissolve one quarter of its weight of common salt, 
and if more salt be added, it will sink to the bottom in a 
solid state. Some fluids will dissolve more of certain 
substances when hot than when cold. Thus w^ater, 
w^hen hot, will dissolve a much larger quantity of nitre 
than when cold. 

Sediment. The heavy parts of liquids which fall to 
the bottom. 

Semi. In composition, this term universally means half. 

Simple. This term is applied very generally in every 



CHEMltAL TERMS EXFLAINED. 4o 

department of nature, to designate that which is not 
compound. 

Solution, The dispersion of the particles of a solid 
body in any fluid, in so equal a manner that the compound 
liquor shall be perfectly and permanently clear and 
transparent. This takes place when the particles of the 
fluid have an affinity or elective attraction for the parti- 
cles of the solid. When solid particles are only dispersed 
in a fluid by mechanical means, it is mixture, not solu- 
tion, and the compound usually opaque and muddy. 

Specific gravity. The density of the matter of which 
any body is composed, compared to the density of an- 
other body, assumed as the standard. This standard is 
pure distilled water, at the temperature of 60'^ F. To 
determine the specific gravity of a solid, w^e weigh it, 
first in air, and then in water. In the latter case, it 
loses of its weight a quantity precisely equal to th€ 
weight of its own bulk of water ; and hence, by com- 
j>aring this weight with its total weight, we find its spe- 
cific gravity. The rule therefore is, divide the total 
weight by the loss of weight in water, the quotient is 
the specific gravity. If it be a liquid or gas, w^e \veigh 
it in a glass or other vessel of known capacity ; and di- 
viding the weight by the same bulk of water, the quo- 
tient is, as before, the specific gravity. 

Spirit, This name was formerly given to all volatile 
substances collected by distillation. Three principal 
kinds were distinguished : inflammable or ardent spirits, 
acid spirits, and c\lkaline spirits. The w^ord spirit is nov/ 
almost exclusively confined to alcohol. 

Stratification, x4n operation in which bodies are placed 
alternately in layers, in order that they may act upon 
each other when heat is applied to them, it is nearly 
the same with cementation, but cementation is more par- 
ticularly applied to the cases already noted. 

Sub, This term is applied when a salifiable base is 
predominant in a compound, there being a deficiency of 
the acid: as suhcarhonate of potassa, subcarbonate of 
soda. 



44 CHEMISTRY. 

Sublimation. A process by which volatile substances 
are raised by heat, and again condensed in a solid form. 
This process differs from evaporation only in being con- 
fined to solid substances. It is usually performed either 
for the purpose of purifying certain substances, and dis- 
engaging them from extraneous matters ; or else to re- 
duce into vapour, and combine, under that form, princi- 
ples which would have united with greater difficulty if 
they had not been brought to that state of extreme 
division. 

As all fluids are volatile by heat, and consequently 
capable of separation, in most cases, from fixed matters, 
so various solid bodies are subjected to similar treatment. 
Fluids are said to distil, solids to sublime ; though some- 
times both are obtained in one and the same operation. 
If the subliming matter converts into a solid hard mass, 
it is commonly called a sublimate ; if into a powdery 
form, flowers. 

The principal subjects of this operation are, volatile 
alkaline salts ; neutral salts, composed of volatile alkali 
and acids, as sal ammonia ; the salt of amber, and flow- 
ers of benzoin, mercurial preparations, and sulphur. 
Bodies of themselves not volatile are frequently made to 
sublime by the mixture of volatile ones ; thus iron is car- 
ried over by sal ammoniac in the preparation of the 
flores martiales, or ferrum ammoniatum. 

The fumes of solid bodies in close vessels rise but a 
little w^ay, and adhere to that part of the vessel where 
they concrete. 

Super. This term is applied to several saline sub- 
stances, in which there is an excess of one of its con- 
stituents beyond what is necessary to form the ordinary 
compound ; as supersulphate of potassa, supercarbonate 
of soda, &c. 

Trituration, The act of reducing a solid body into a 
subtile powder; as woods, barks, &c. It is performed 
mostly by the rotary motion of a pestle in metallic 
glass, or wedgewood mortars. 

Uret. The compounds of simple inflammable bodies 



CHEMICAL APPARATUG DESCRIBED, 45 

with each other, and with metals, are commonly desig- 
nated by this word ; as sulphuret of phosphorus, carburet 
of iron, &c. The ternis bisulphuret, bisulphate^ &c., 
applied to compounds, imply that they contain twice the 
quantity of sulphur, sulphuric acid, &c. existing in the 
respective sulphuret, sulphate, &c. 

Viscidity. Glutinous, sticky, like the bird-lime. 

Volatilization. The reducing into vapour, or the aeri- 
form state, such substances as are capable of assuming it. 

Way^ dry. When the chemist decomposes substances 
by the agency of heat, he is said to operate in the dry 
way. 

Way^ humid. When the decomposition is produced 
by water or other fluids, the effect is said to be produced 
in the humid way. 



APPARATUS DESCRIBED. 



Acetometer. An instrument for estimating the strength 
of vinegars. 

Adopter. A chemical vessel with two necks used to 
combine retorts to the cucurbits or matrasses, with 
retorts instead of receivers. 

Mrometer. An instrument for making the necessary 
corrections in pneumatic experiments to ascertain the 
mean bulk of the gases. 

Alembic. A chemical utensil made of glass, metal, or 
earthenware, and adapted to receive volatile products 
from retorts. It consists of a body to which is fitted a 
conical head, and out of this head descends laterally a 
beak to be inserted into the receiver. 

Alkalometer. The name of an instrument for deter- 
mining the quantity of alkali in commercial potassa and 
soda. 

Almometer. The name of an instrument to measure 
the quantity of exhalation from a humid surface in a 
given time. 



46 CHEMISTRY. 

Barometer. An instrument to determine the weight 
of air ; it is commonly called a weather-glass. 

Blow-pipe, A very simple and useful instrument. 
That used by the anatomist is made of silver or brass, 
of the size of a common probe, or larger, to inflate ves- 
sels and other parts. 

The chemical blow-pipe is made of brass, is of about 
one-eighth of an inch diameter at one end, and the other 
tapering to a much less size, with a very small perfora- 
tion for the wind to escape. The smaller end is levelled 
on one side. Berzelius, in a late excellent treatise on 
the use of the blow-pipe in chemistry and mineralogy, 
gives the preference to Ghan's construction, with an 
additional bent-beak, for a laboratory blow-pipe, and to 
Wollaston's for a pocket instrument. 

Calorimeter. An instrument by which the whole 
quantity of absolute heat existing in a body in chemical 
union can be ascertained. 

Clinometer. An instrument for measuring the dip of 
mineral strata. 

Cryophorus. The post-bearer, or carrier of cold ; an 
elegant instrument invented by Dr. Wollaston, to demon- 
strate the relation between evaporation at low tempera- 
ture, and the production of cold. 

Crucible. This vessel is employed in the melting of 
metals, and other operations of fusion. They are made, 
for low heats, of earthenware or porcelain, but for strong 
heats, of clay and sand, or clay and powdered plumbago. 
Hessian and Dutch crucibles, which are made of refrac- 
tory clay and sand, are generally the most approved; 
but modern chemists have an invaluable acquisition in 
platina, which is often made into crucibles, and will 
bear, without fusion or injury, a greater heat than any 
other known substance. 

Cupel. A shallow earthen vessel like a cup, made of 
phosphate of lime, which suffers the baser metals to pass 
through it, when exposed to heat, and retains the pure 
metal. This process is termed cupellation. 

Cucurbits, or matrasses, are glass, earthen, or metallic 



CHEMICAL APPARATUS DESCRIBED. 47 

vessels, usually of an egg-shape, and open at the top. 
They are used for the purposes of digestion, evapora- 
tion, solution, &c. 

Digester. A strong and tight iron kettle or copper, 
furnished with a valve of safety, in which bodies may 
be subjected to the vapour of water, alcohol, or ether, 
at a pressure above that of the atmosphere. 

Eudiometer, An instrument by which the quantity of 
oxygen and nitrogen in atmospherical air can be ascer- 
tained. Several methods have been employed, all 
founded upon the principle of decomposing common air 
by means of a body which has a greater affinity for the 
oxygen. 

Evaporating vessels. These are made of glass, wood, 
metal, porcelain, or Wedgewood's ware. Those of the 
last-mentioned composition are very convenient, as they 
are, like glass, easily kept clean, and are not very subject 
to crack by changes of temperature. They are gene- 
rally in the form of shallow basins, and when the matter 
deposited in them would be apt to burn to the bottom, 
and be injured, if not strictly attended to, they are 
placed over the fire in a vessel filled with sand, which is 
then called a sand-bath. When even this heat would 
prove too great, the heat of boiling w^ater is used instead 
of sand. 

Furnace, The furnaces employed in chemical opera- 
tions are of three kinds: 1. The evaporatory furnace, 
which has received its name from its use : it is employed 
to reduce substances into vapour by means of heat, in 
order to separate the more fixed principles from those 
which are more volatile. 

2. The reverheratory furnace, which name it has 
received from its construction, the flame being prevented 
from rising. It is appropriated to distillation. 

8. The forge furnace. In which the current of air 
is determined by the bellows. 

Gasometer. Vessels constructed for the retention of 
gas, and for facilitating the drawing of it ofT as wanted, 
are called gasometers. They are much varied in their 



48 CHEMISTRY. 

construction ; but those on the principle we shall now 
describe, are amongst the most simple, and answer per- 
fectly welL They are a cylindrical vessel of glass, or 
japanned tin-plate, nearly filled with water, and having a 
tube in the middle open at the top, and branching at the 
bottom, through the side of the vessel, to which a stop- 
cock is attached. Within this vessel, there is another 
cylindrical vessel, generally of glass, open at the bottom, 
which is inverted, and suspended by lines which go over 
pullies, and have weights attached to them, which hang on 
the outside, to balance the inverted vessel. While the stop- 
cock at the bottom remains shut, if the vessel be pressed 
downwards, the air inclosed within it, will remain within 
in the same situation, on the principle of a diving bell ; 
but if the cock be opened, and the inverted vessel be 
pressed down, the air inclosed within it will escape 
through the cock, and if a blow-pipe be attached to this 
cock, a stream of the gas may be thrown upon lighted 
charcoal, or any other body. By means of a graduated 
rod on the top of the inverted vessel, the quantity thrown 
out is exactly ascertained ; this rod being so divided as to 
express the contents of the inner vessel in cubic feet 

Goniometer, An instrument for measuring the angles 
of crystals. 

Hydrometer. The best method of weighing equal 
quantities of corrosive volatile fluids, to determine their 
specific gravities, appears to consist in enclosing them in 
a bottle with a conical stopper, in the side of which 
stopper a fine mark is cut with a file. The fluid being 
poured into the bottle, it is easy to put in the stopper, 
because the redundant fluid escapes through the notch, 
or mark, and may be carefully wiped ofifl Equal bulks 
of water, and other fluids, are weighed by this means to 
a great degree of accuracy : care being taken to keep 
the temperature as equal as possible, by avoiding any 
contact of the bottle with the hand, or otherwise. The 
bottle itself shows with much precision, by a rise or fall 
of the liquor in the notch of the stopper, whether such 
change has taken place. 



CHEMICAL APPARATUS DESCRIBED. 49 

The hydrometer of Fahrenheit consists of a hollow 
ball, with a counterpoise below, and a very slender stem 
above, terminating in a small dish. The middle, or half 
length of the stem, is distinguished by a fine line across. 
In this instrument every division of the stem is rejected, 
and it is immersed in all experiments, to the middle of 
the stem, by placing proper weights in the little dish 
above. Then, as the part immersed is constantly of the 
same magnitude, and the whole weight of the hydrom- 
eter is known, this last weight added to the weights in 
the dish, will be equal to the weight of the fluid dis- 
placed by the instrument, as all writers on hydrostatics 
prove. And accordingly, the specific gravity for the 
common form of tables, will be had by the proportion : 
as the whole weight of the hydrometer and its load, 
when adjusted in distilled water, is to the number 1000, 
&c., so is the whole weight when adjusted to any 
other fluid to the number expressing its specific gravity. 

Hypocleptcium, A chemical vessel for separating li- 
quors, particularly the essential oil of any vegetable, 
from the water ; and named because it steals, as it were, 
the water from the oil. 

Hygromete7\ The state of the atmosphere, with re- 
spect to dryness or moisture, is measured by this instru- 
ment. It is sometimes called hygroscope. 

Mortar. A sort of mould, a vessel to pound in. 

Muffles, In cupellation, it is necessary for the con- 
tents of the cupel to be expired to the access of air ; 
the cupel must not, therefore, be used in a closed fur- 
nace, or be surrounded with fire. A kind of small ovens 
are therefore employed, which are called muffles. They 
are made of the same material as crucibles, and the 
cupel being put into them, they are exposed to the heat 
of the furnace. They are also used in enamelling, and 
other operations, where heat is required, while the con- 
tact of the fire must be taken ofK 

Pyrometer. As the common mercurial thermometer 
cannot be employed to ascertain degrees of heat above 
500 or 550 degrees of Fahrenheit, it is totally inappliea- 
5 



50 CHEMISTRY. 

ble to most of the operations carried on in furnaces and 
ovens : yet in a variety of manufactures and chemical 
operations, success depends upon the adjustment of the 
heat with a degree of nicety which the most experienced 
persons are incapable of determining by mere observa- 
tion. To supply this desideratum, Wedgewood contrived 
an instrument called a pyrometer^ the range of which 
extends to 32,000 degrees of Fahrenheit's scale. Its 
utility is derived from the property which clay has of 
contracting in proportion to the degree of heat to which 
it is exposed. This contraction is permanent, and a less 
degree of heat than that which the clay has experienced, 
wull not alter its dimensions. If, therefore, a piece of 
clay, of a given bulk, be exposed to the heat of a fur- 
nace, it may occasionally be taken out, and upon being 
applied to a gauge, the degree of its contraction may be 
ascertained, and consequently the greatest heat to which 
it has been exposed, provided this gauge has* been grad- 
uated by previous experiments. Wedgewood constructed 
this pyrometer by duly availing himself of these cir- 
cumstances. 

The pyrometic pieces of clay intended to be used io 
any given scale, should be exactly of the same composi- 
tion, as different clays contract in different degrees by 
the same heat. To guard against the disadvantage of a 
difference, Wedgewood offered to the Royal Society a 
bed of Cornish clay, sufficiently extensive to furnish the 
world for ages. 

The gauge for measuring the diminution which the 
pieces of clay suflfer from the action of fire, is made of 
two pieces of brass, tv^^enty-four inches long, with the 
sides exactly plane, divided into inches and tenths, fixed 
five-tenths asunder at one end, and three-tenths* of an 
inch at the other end, upon a brass plate ; and the py- 
rometic pieces are made at first so as just to fit the wider 
end. The pieces of clay are generally made about one 
inch long ; but if their breadth be just equal to that of 
the wider end of the gauge, viz. five-tenths of an inch, 
their dimensions in other respects are not material. 



CHEMICAL APPARATUS DESCRIBED. 51 

It is obvious, that in proportion to the shrinking of the 
clay by heat, it will slide farther and farther towards 
the narrow end of the converging scale, one side of 
which is divided into tenths of an inch ; and every divi- 
sion, of which it contains 240, answers to a 600th part 
of the breadth of the little piece of clay. One degree 
of the pyrometer is equal to 130 degrees of Fahrenheit's 
scale. 

The regular shrinking of clay by heat, does not com- 
mence at a lower degree than a red heat fully visible in 
daylight ; and this heat is equal to 1077^^ degrees of 
Fahrenheit, or about 500 degrees above the point at 
which the mercurial thermometer terminates. It be- 
comes therefore desirable to measure the range of tem- 
perature to which neither of these instruments applies ; 
but nothing has yet been contrived which answers the 
purpose in a simple manner. 

The pyrometic pieces of clay should be exposed as 
nearly as possible to the same heat as the material, the 
heat received by which they are intended to measure. 
For this purpose, they are usually placed close to it, and 
in the same crucible ; but when the contents of the cru- 
cible might adhere to them, they are inclosed in a small 
case, made of crucible clay ; and as they may be re- 
duced in any degree, while their breadth is retained, the 
pyrometic piece may generally be introduced without 
difficulty into any but very small crucibles; and they 
may be disposed by the side of very small crucibles, with- 
out much hazard of receiving their heat materially soon- 
er, or with greater intensity than the contents of the 
crucible. 

The pyrometic piece may be taken out of the fire 
during any period of the process, and instantly cooled in 
water, so as to be ready for measuring in the gauge in 
the space of a few seconds. It will not crack, expand, 
contract, or sustain any other injury ; and may be imme- 
diately replaced in the strongest fire, to resume its office 
of indicating higher degrees of heat than what it has 
already been exposed to, 



52 CHEMISTRY. 

The following table will give a better idea of the 
heats designated by the pyrometer, than any general 
remarks : 

Fahr. Wedgw. 

Extremity of the scale of the pyro- 
meter 02270° 240^ 

Greatest heat of an air furnace, 8 

inches square 21877 160 

Cast-iron melts 17977 130 

Greatest heat of a common smith's 

forge 17327 125 

Welding heat of iron, greatest - - 13427 95 

Welding heat of iron, least - - ^ 12777 90 

Fine gold melts 5237 32 

Fine silver melts 4717 28 

Swedish copper melts 4587 27 

Brass melts 3807 21 

Heat by which enamel colours are 

burnt on 1857 6 

Red-heat fully visible in daylight - 1077 

Red-heat fully visible in dark - - 947 1 

Mercury boils 600 3/-7o^o 

Water boils 212 6/-\V 

-Vital-heat 97 7^VoV 

Water freezes 32 87|.f^ 

Proof spirit freezes ^^oW 

The point at which mercury congeals, 
consequently the limit of the mer- 
curial thermometers, about - - 40 8yf ^^ 

Wedgewood found by analysis, that the clay of which 
his pyrometer pieces were formed, consisted of two parts 
of pure siliceous earth, to three parts of pure argillaceous 
or aluminous earth. 

The use of the pyrometer shows in a remarkable 
manner the inaccuracy of the common mode of express- 
ing the highest degrees of heat by estimation. Thus the 
heat at which copper melts is called a white heat, though 
it is only 27"^ of the pyrometer ; the welding heat of iron, 
or 90°, is also a white heat; even 130"^, and upwards, is 
still a white heat. These examples show very clearly 



CHEMICAL APPARATUS DESCRIBED. 53 

that the temperature of bodies in furnaces is raised in a 
manner of which we have no idea, unless the materials 
subjected to it are such as to give us the necessary in- 
formation. 

Receiver, or recipients. These vessels are usually 
glass for small operations, for receiving the volatile pro- 
duct from a retort or alembic; they are adapted to the 
neck of the before-mentioned apparatus, and secured by 
luting. 

Retorts, These are globular vessels, formed with a 
long neck, and are made of earthenware, glass, or metal, 
according to the use for which they are designed. They 
are used in distillations, and most frequently for those 
which require a degree of heat superior to that of boil- 
ing water. The tube of a retort is usually called a beak. 

Glass retorts should be very thin,, and of a uniform 
substance in every part; otherwise, from the inequality 
of their expansion, they will crack with the application 
of a very slight heat : they cannot also be e^^posed to 
the fire, unless defended by coating, which is generally 
some earthy composition. Chaftal particularly recom- 
mends, for this purpose, fat earth which has been suffer- 
ed to rot some hours in water ; it must then be kneaded 
with horse dung, and formed into a soft paste, which 
must be equally spread over every part of the retort to 
be exposed to the fire. The adhesion of this coating is 
such, that should the retort crack during the operation, 
the distillation may still be carried on. The retorts used 
over a lamp are not coated. 

Thermometer. The thermometer is a well known 
instrument for measuring the actual or relative tempera- 
ture of bodies. Its properties are dependent upon the 
disposition of all bodies to acquire an equal degree of 
sensible heat or cold, and on the effects of heat in ex- 
panding some substances, the changes of the dimensions 
of which are examined by a scale of equal divisions. 
Mercury expands by heat, and contracts by cold, with 
greater uniformity than any other known fluid; it is, 
therefore, the most proper and the most commonly used 
5* 



54 CHEMISTRY. 

for thermometers, vvliich are constructed in the following 
manner : 

The first requisite is a glass tube, which may be 
obtained at the glass house, having a bulb at one end, 
which, together with part of the tube, is filled with 
purified mercury,^ which, when introduced into the tube, 
is boiled to expel the air or moisture that might be at- 
tached to it; and at the moment it is in ebullition, the 
extremity of the tube, being drawn to a point by means 
of a blow pipe, it is hermetically sealed, to prevent any 
air from entering the tube. Or if the scale be graduated 
only to 212°, the ball is plunged into boiling water, the 
point to which the mercury ascends accurately marked. 
For the purpose of graduating the scale, the thermome- 
ter is plunged into melting ice, and the place where the 
mercury stands marked. From the freezing to the boil- 
ing point on Fahrenheit's scale, is 180°, or equal parts; 
and similar parts are taken above and below, for extend- 
ing the scale. 

Fahrenheit's is the one commonly used in this country, 
and in Great Britain. The space between the freezing 



"^ Mercury is generally purified by distillation; but as this ope- 
ration may not be convenient to some, I shall mention Dr. Priest- 
ley's mode of purifying it, which is remarkable for its simplicity, 
and has an excellent effect. Let a strong 10 or 12 ounce phial, 
with a ground stopper, be a quarter filled wdth mercury to be puri- 
fied ; put in the stopper, hold the bottle inverted with both, hands, 
and shake it violently, by striking the hand that supports it against 
the knee. After twenty or thirty strokes, take out the stopper, and 
blow into the phial with a pair of bellows, to change the air. If 
the mercury is not pure, the surface will become black in a shoi*t 
time ; and if very foul, the black coat v/ill appear coagulated. In- 
vert the phial, stopping it with the finger, and let out the running 
mercury. Put the coagulated part into a cup by itself, and press 
it repeatedly with the finger, so as to get out the mercury entan- 
gled in it. Put both portions of mercury into the phial again, and 
repeat the process till no more black pov/der separates. 

After the mercury has been thus purified from its admixture 
with baser metals, it should be boiled for about half an hour, to free 
it from the moisture which it is apt to contain. It may then be 
nearly cooled, when it is ready for tlie use of thermometers, 



CHEMICAL APPARATUS DESCRIBED. 55 

and the boiling points is divided into 180^, but the scale 
begins at that point of temperature which is produced 
by a mixture of pounded ice and muriate of ammonia, 
or muriate of soda, which is 32° lower, making the w hole 
distance 212°. 

The centigrade thermometer is divided into one hun- 
dred degrees, between the freezing and boiling points. 
The freezing point is marked 0, the boiling 100°. 

In Reaumur's thermometer, the space between the 
freezing and boiling points is divided into eighty degrees. 
The freezing point is marked 0, the boiling 80°. 

The Russian thermometer, commonly called Delisle's, 
begins its graduation at the boiling point, and increases 
to the freezing. The boiling point is marked 0, the 
freezing 150°. 

Other fluids, besides mercury, are sometimes used, 
such as linseed oil and alcohol ; the latter is used partic- 
ularly for measuring low degrees of temperature, where 
mercury would become solid. 

For nice chemical experiments, an air thermometer is 
fsometimes used. The bulb of air thermometers is filled 
with common air only, and its expansion or contraction 
is indicated by a small drop of any coloured liquor, 
which is suspended within the tube, and moves up and 
down according as the air within the bulb or tube ex- 
pands and contracts. 

In general, air thermometers, however sensible to the 
change of temperature, are by no means accurate in 
their indications. 



56 CHEMISTRY. 

Rentarks on Apparatus, 

The list of chemical apparatus might still be farther 
enlarged, which are of less general application than 
those already noticed. It will be evident, that in a 
place where, as in a laboratory, several mechanical 
operations are usually resorted to, that a large strong 
table or bench is of considerable importance. Conve- 
nient small tables or blocks of wood, should also be at 
hand, for supporting mortars, levigating stones, an anvil, 
&c. A large vice, the use of which implies that of 
hammers, rasps, files, saws, and other implements for 
working wood and metals. Rods of glass, or porcelain, 
or even clean straws, are used for stirring mixtures in 
glasses and other vessels. 

It is proper to have a pair of bellows ; shovels, tongs, 
and pokers, for managing the fire, are of course neces- 
sary ; and tongs of different shapes, for taking out cru- 
cibles, muffles, &c., from the furnace, which should also 
be at hand. 

A plentiful supply of water should also be at hand, 
together with fuel, and many other things which it is 
needless to allude to. Distilled water to be Uvsed in 
analyses, and almost all operations which are to be con- 
ducted with exactness. 

In such a place as a laboratory, where a vast variety 
of utensils are to be arranged, and where the eye ought 
to commeind the situation of every individual article, the 
arrangement should be such as to be at once commodious 
and easily maintained. The rule, to let every article 
have one place, and but one place, is very simple, and 
the only sure method of keeping good order. 

It ought to be observed, that it is injurious to the ad- 
vancement of chemical knov^^edge, to give currency to 
the idea, that no discoveries, or improvements, can he 
made without the aid of an extensive and costly appa- 
ratus. Every chemist should be a good mechanic, and 
the resources of the mechanic who attends to his pur- 
suits with his whole will, are often sufficient to enable 



SUBSTANCES. 57 

him to accomplish very important ends, at little expense, 
and by very simple means. 

By these, together with a variety of other resources, 
which are promptly suggested to the active mind, and 
which will be different with persons in different situa- 
tions, a demonstration of all the principal facts of chem- 
istry may be obtained, and new experiments carried into 
execution, in some instances without any real expense, 
and in general without much. 



OF SUBSTANCES. 

Meaning of the term simple* 

All substances in nature, when classed according to 
their apparent or sensible properties, may be considered 
either as solid, fluid, aeriform, or ethereal. But they 
may be distinguished by any of these characters, and 
yet be either simple or compound ; but to make this dis- 
tinguishment in the classification of substances, would 
be incompatible with the design of the present work ; 
suffice it, therefore, to say in what manner chemists use 
the term simple. They do not mean by the term simple, 
that the body to which it is applied is absolutely known 
to be simple, but merely that it has never been com- 
pounded, nor is known to be capable of decomposition. 
Hence, a substance at this time called simple, may 
hereafter, by more improved modes of analysis, be 
proved a compound. What modern chemists call simple 
bodies, the ancient chemists call elements, a term which 
is yet sometimes used. 

The combination of a substance with caloric or light, 
is not regarded as moving it out of the class of simple 
bodies, otherwise we could have nothing to denominate 
simple. 



58 CHEMISTRY* 

OF LIGHT. 

The nature of light has occupied much of the atten- 
tion of philosophers, and numerous opinions have been 
entertained concerning it. It has sometimes been con- 
sidered as a distinct substance, at other times as a qual- 
ity ; sometimes as a cause, frequently as an effect ; by 
some it has been considered as a compound, by others as 
a simple substance. Let these considerations be as they 
may, light has an influence upon almost all bodies which 
are exposed to it. It is the source of the colour of vege- 
tables, and in a great measure, if not entirely, of their 
odour. Plants which grow in darkness are devoid of 
colour, in which case they are said to be etiolated or 
blanched. Gardeners avail themselves of this fact to 
render vegetables white and tender. Vegetables so sit- 
uated that the light can only fall freely on one side of 
them, gradually turn to the light, and chiefly shoot out 
in that direction. Some whose stems are flexible, follow 
the course of the sun during the day, and always pre- 
sent the same face towards him. 

The back, fins, and other parts of fish exposed to light, 
are coloured, but the belly, which is deprived of light, 
is always white. 

The vegetable and animal productions of tropical 
countries, are distinguished by brighter colours than 
those of higher latitudes. The cause of this phenome- 
non must be referred to the greater abundance and in- 
tensity of the light, upon the action of which all colour 
is dependent. The superior strength of the perfumes, 
odoriferous fruits, and aromatic resins, of those countries, 
has the same origin. 

All metallic oxides, but especially those of mercury, 
bismuth, lead, silver, and gold, become of a deeper col- 
our by exposure to the rays of the sun ; some of them 
become perfectly revived, others only partially. The 
yellow oxide of tungsten, if exposed to the light, loses 
weight and becomes blue. Green precipitate of iron, 
exposed to the solar light, also becomes blue* 



LIGHT. 59 

Light has a considerable influence on the crystalliza- 
tion of salts, many of which will not crystallize without 
it. Camphor kept in glass bottles, exposed to the light, 
crystallizes in symmetrical figures on that side which is 
turned towards the light ; and spirits of wine, water, 
&c., rising by insensible evaporation in half-filled ves- 
sels, constantly attach themselves to the most enlightened 
sides of the vessel. 

It is not to be supposed that these effects are produced 
by the mere contact of light; on the contrary, we have 
abundant proofs that light has the power of entering 
into the composition of bodies, and of being afterwards 
extricated from them without any alteration. A great 
number of substances become luminous after having 
been exposed to light, — a property rendered obvious by 
carrying them instantly from the light to the dark : the 
diamond is a body of this kind ; indeed, if the human 
hand be thrust into a strong light, through an aperture 
in a perfectly dark room, it will, when drawn in, and the 
aperture closed, be plainly seen, although the other hand 
is totally invisible. 

Light is not homogeneous : it is composed of different 
coloured rays, possessing different refrangibility. The 
prismatic colours have been divided into seven, viz : red, 
orange, yellow, green, blue, indigo, and violet. Red is 
the least, and violet the most refrangible. 

The rays of light must be extremely rare, for they 
cross each other in all possible directions, without the 
least apparent disturbance. 

The solar rays have been divided into three different 
kinds. 1. Colorific, or those producing colour. 2. Cal- 
orific, or those producing heat. 3. Deoxydizing, expel- 
ling oxygen, and restoring the oxides of metals to their 
metallic state. 

The different sources from which light is emitted in a 
visible form, are : L The sun and fixed stars. 2. Com- 
bustiorif which is the act of combination of the combus- 
tible with oxygen ; of course, the light emitted must 
have existed previously, combined with the combustible 



60 CHEMISTRY. 

or With oxygen. 3. Heat ; when the body becomes 
luminous by being heated in the fire, it is said to be red 
hot ; and it is found that all bodies that are capable of 
enduring the requisite degree of heat, without decompo- 
sition or volatilization, begin to emit light at the same 
temperature. 

A number of terms are made use of and explained 
under the science of optics, which might prove instruct- 
ing. 

OF CALORIC. 

What is denominated heat, is a sensation produced by 
a substance called caloric, which penetrates all bodies, 
diminishes the attraction of their several parts, and uni- 
formly expands their dimensions. 

By means of this powerful agent, solid metals are 
fused ; liquids rarified ; and almost all substances in na- 
ture are converted into elastic, compressible, or aeriform 
fluids. 

It has been asserted by Levoiser, that all bodies, of 
whatever kind, may exist in three different states, solid, 
fluid, and aeriform. 

Caloric is found to exist under a variety jof forms or 
modifications. It is said to be free or radiant, and is 
commonly called heat or temperature; it is that heat 
which is perceptible to our senses, and affects the ther- 
mometer, whatever be its degree, or the source whence 
it is derived. 

Combined caloric is that which does not affect the 
thermometer, and is not perceptible by our senses ; it is 
retained in bodies by the force of affinity or attraction, , 
and becomes a part of their substance. 

Heat differs from caloric in this : one is the cause, the - 
other the effect. The latter means that which produces 
heat ; while the former is merely the sensation. 

Liquids are combinations of solids with a larger por- 
tion of caloric than they naturally contain. 

Instruments for measuring the relative degrees of heat, 
are called pyrometers, and thermometers, with suitable^ 
scales attached, indicating the degrees. 



CALORIC. 61 

The states in which bodies exist, admit of different 
degrees of density or consistence, arising, for the most 
part, from the different degrees of caloric which they 
contain. Solids are of different degrees of density, from 
that of gold to that of jelly ; liquids, from the consist- 
ence of melted glue, or melted metals, to that of ether. 
The different elastic fluids are susceptible of different 
degrees of density. 

Bodies admit of different degrees of consistence with- 
out changing their state, merely through the agency of 
caloric. 

According to late theory, caloric is composed of parti- 
cles perfectly separate from each other, every one of 
which moves with great velocity in a certain direction. 
These directions vary infinitely, the result of which is, 
that there are rays or lines of these particles, moving 
with immense velocity, in every possible direction. Ca- 
loric, then, is universally diffused, so that when any por- 
tion of space happens to be in the neighbourhood of an- 
other, which contains more caloric, the colder portion 
receives a portion of the calorific rays from the latter 
sufficient to restore an equilibrium of temperature. This 
radiation not only takes place in free space, but extends 
also to bodies of every kind. Thus you may suppose 
that every body whatsoever, is continually sending forth 
rays, when the body is surrounded with an elastic medium, 
or in a vacuum. 

These rays are capable of reflection and refraction. 

The manner in which bodies are affected by rays pro- 
ducing heat, differs in different substances, and is very 
much connected with their colours. 

Bodies that absorb the most light and of course radiate 
heat, are heated the most when exposed to solar or ter- 
restrial rays. 

Black bodies in general are more heated than red, red 
more than green, green more than yellow, yellow more 
than white. 

All bodies are, in a greater or less degree, conductors 
of caloric. 
6 



62 CHEMISTRY. 

Bodies with respect to caloric are divided into two 
kinds, good and bad conductors. 

Metals and liquids are good conductors of caloric, but 
sillc, cotton, wool, wood, feathers, &c., are bad conductors. 

A short rod of iron put into the fire at one end, will 
very soon become hot at the other end ; but a piece of 
wood or cane of the sanne length, placed precisely in the 
same circumstances, may be burnt to ashes at one end, 
without producing scarcely a sensation of warmth at the 
other. 

The facility with which bodies are cooled or heated, 
is in proportion to their conducting power. 

Good conductors both give and receive caloric quicker, 
and in a given time more abundantly, than bad conduct- 
ors, which is the cause of their feeling hotter or colder ; 
though they may be in fact of the same temperature, as 
indicated by the thermometer. 

In general, the most dense bodies are the best con- 
ductors of heat ; probably, because the denser the body, 
the more the number of points that come into contact 
with caloric. 

Deep lakes are not frozen in winter. This is owing to 
the circumstance of cold air being constantly presented 
to the surface of the lake, which causes a portion of 
w^ater to lose its temperature, and thus becoming heavier, 
falls gradually to the bottom, while the warmer water 
from below ascends, forming a new surface in its place. 

Caloric dissolves water and converts it into steam, by 
insinuating itself between the particles which are so 
minutely divided as to become invisible. 

When vapour of boiling water first issues from the 
vessel, it is invisible, because it is then completely dis- 
solved by caloric. But when it comes in contact with 
the cold air, it is condensed, in consequence of a part of 
the caloric being imparted to the air. The particles of 
water being in a great measure deprived of their sol- 
vent, gradually collect, and became visible in the form 
of steam, and when further deprived of caloric, return 
to their liquid state. 



OXYGEX. 63 

The atmosphere dissolves water by means of the 
caloric which it contains. This is called evaporation, 
and differs from vaporization, which is caused by culi- 
nary heat 

The earth being a great radiator of caloric, parts with 
its heat more readily than air. When the solar heat 
declines and entirely ceases in the evening, the earth 
rapidly cools by radiating heat towards the skies; whilst 
the air has no means of parting with its heat, but by 
coming in contact with the cool surface of the earth, to 
which it communicates its caloric. The solvent power 
being thus reduced, the water is deposited in small drops 
called dew. 

OF OXYGEN. 

OxYGEiv is the name given to the solid particles of 
oxygen gas, which is a combination of oxygen, caloric, 
and light, and is the simplest form in which oxygen can 
be obtained. Oxygen is called the radical or base of the 
gas ; and the same mode of expression is used in other 
cases. 

Oxygen gas was discovered by Dr. Priestley, on the 
1st of August, 1774. It is invisible, perfectly elastic like 
common air, and possesses neither taste nor smell. It is 
740 times lighter than water. Its weight to atmospheric 
air, is as 1103 to 1000. 

Oxygen has never been procured in an uncombined 
state. Its greatest purity is that of gas. It is not made 
solid by any degree of cold, and therefore differs in this 
respect from vapours which may be condensed into a 
liquid, and converted into a solid. 

Oxygen enters into chemical combination with a great 
number of substances, in which it exists in a concrete or 
solid state; it is by the application of heat, or of acids, 
to some of the substances containing it, that it is usually 
procured in the form of gas. 

Oxygen gas may be obtained with the greatest facility 
and purity, from hyper-oxymuriate of potass. A small 
retort must be partly filled with this salt, and exposed 



64 CHEMISTHY. 

to the heat of a lamp ; the salt melts, and oxygen is 
extricated in abundance, as it is held by this singular 
substance in a state of great concentration, and by a 
ver}^ weak affinity. 

Ingenhouz obtained from four ounces of nitrate of 
potass, melted with a little slacked lime, 3000 cubic 
inches of this gas. Let any quantity of this salt be put 
into an earthern or iron retort, to the extremity of which 
is adapted a bent tube, terminating in the pneumatic 
trough. The retort must be gradually made red-hot, 
when the oxygen gas will be rapidly disengaged, and 
will be very pure. 

When considerable quantities of oxygen are required, 
the black oxide of manganese is most frequently used, 
as it is the cheapest article that can be employed, and 
supplies the gas in a good degree of purity. The 
manganese is put into a retort, which is made red-hot, 
and the gas is collected by the pneumatic apparatus, as 
in using nitrate of potass. One pound of the best 
manganese will yield upwards of 1400 cubic inches of 
the gas. The retort is easily cleared of the manganese 
w^hen the experiment is ended ; and if the manganese 
that has once been used, be exposed to the air for some 
time, it will serve again; but the cheapness of the arti- 
cle renders this of little consequence. 

Red oxide of mercury, and of lead, yield oxygen in 
the same manner as manganese. 

Oxygen gas is the only one that can be breathed by 
animals for any length of time with impunity. The 
power of atmospheric air in supporting respiration, is 
owing to the oxygen. 

In respiration, a quantity of atmospheric air is taken 
into the lungs ; the oxygen disappears, and a quantity of 
carbonic acid gas, equal in bulk, is formed in its stead. 
A reciprocal influence is exerted between this aerial 
fluid and the circulating blood ; and the continuance of 
life is dependent upon the due exercise of this influence, 
which appears by the conversion of oxygen into carbonic 
acid. 



OXYGEN. 65 

Ammals confined in oxj^gen gas will live four or five 
times longer than when confined in atmospheric air. 

It may be breathed by men for some time, without 
producing any other effect than a sensation of warmth 
and slight stricture of the chest. 

Oxygen forms about 22 per cent, of the atmospheric 
air : the rest is nitrogen or azotic gas, except a small 
quantity of carbonic acid. 

Oxygen combines with all the metals ; and in that 
state, they are called metallic oxides, depriving them of 
their metallic lustre, and giving them an earthy or rusty 
appearance. 

Some of the metals become oxidized, or are rusted by 
mere exposure to the damp atmosphere. 

Iron, exposed to the weather, soon becomes rusty, by 
attracting oxygen from the air or water. 

All oxides are heavier than the metal, in proportion 
to the quantity of oxygen with which they are com- 
bined. 

Many of the metals are capable of combining with 
different proportions of oxygen. Those with one propor- 
tion are called protoxides ; of two, deuioxides ; those of 
three, tritoxides. 

A metal combined with the greatest proportions of 
oxygen is called peroxide. 

Oxygen has a powerful effect on vegetable colours, 
producing the various tints of shade which we behold in 
this department of nature. 

Yarn, when taken from the blue vat, is green, but, on 
exposure to the air, it imbibes oxygen, and is changed to 
a blue. 

It is well known to the dyers, that they cannot produce 
a good black without exposing their stalls to the air. 

Vegetable colours fade on exposure to the sun, which 
is probably owing to this principle : the oxygen which 
previously existed in the colouring matter in a solid form, 
is rendered aeriform by the rays of the sun, and is evolved 
in the form of gas. 
6* 



66 CHEMISTRY. 

OF NITROGEN. 

Nitrogen is the basis of the nitric acid. It exhibits 
itself in its simplest state as a gas. It was formerly called 
azote, because it was destructive to animal life. 

Nitrogen gas is most easily described by including 
many of its negative qualities. It has no taste ; it neither 
reddens vegetable blue colours, nor precipitates lime- 
water ; it is not absorbed by water. It unites to oxygen 
in several proportions ; it also unites to hydrogen. 
Though incapable of being breathed above its base, 
nitrogen is a component portion of all animal substances. 
It is lighter than oxygen. Dr. Black found that a vessel 
of 1000 cubical inches, which will contain 315 troy grains 
of atmospheric air, will contain 335 of oxygen gas, but 
only 297 of nitrogen gas, 

Nitrogen gas may be variously obtained. If the oxy- 
gen be extracted from the atmospheric air, this substance 
will remain, and will generally be very pure, unless the 
oxygen has been extracted by respiration. If iron filings 
and sulphur, moistened with water, be put into a jar 
containing atmospherical air, this gas will, in a day or 
two, be all the air that remains in the jar, as the oxygen 
will be absorbed by the iron and sulphur. Phosphorus, 
or sulphuret of lime or potass, inclosed with common air 
in a jar, will produce a similar effect. 

Nitrogen gas may likewise be obtained from animal 
substances. For this purpose, put some small pieces of 
lean muscular flesh into a retort, and cover them with 
weak nitric acid. The heat of a lamp will extricate 
the gas, which may be collected by the pneumatic 
apparatus. 

It has been conjectured that nitrogen is not a simple 
substance, but no experiments have decisively proved this. 

Atmospherical air contains 78 parts in the 100, by 
measure of nitrogen gas ; the 22 remaining parts, or 
oxygen, being thus largely diluted, becomes proportion- 
ately less intense in its stimulating effects, and fit for the 
purposes of life, the length of which is increased by this 



HYDROGEN. 67 

source of moderation in its course. By mixing pure 
nitrogen gas and oxygen gas in the proportions just men- 
tioned, a gas having all the properties of atmospherical 
air is tlie result. 

Though animal life cannot be sustained for a moment 
by nitrogen gas, yet it is congenial to vegetables, and 
appears to be a part of their food ; they derive it from 
its combinations with oxygen in atmospherical air. 

OF HYDROGEN. 

The third and last substance, which, in its simplest 
form, can only be obtained in an aerial state, is called 
hydrogen. This gas has long been generally known by 
the name of injiammahle air ; it is the gas which miners 
call fire damp. 

Hydrogen with oxygen forms water ; and it is by the 
decomposition of w^ater that chemists obtain it in the 
greatest abundance and purity. For this purpose, iron 
tilings or turnings, or granulated zinc, are put into a 
retort, and covered with sulphuric acid diluted with four 
times its weight of w^ater. A violent effervescence 
ensues, a large quantity of gas is evolved, and issuing 
from the retort, is collected in the usual manner by the 
pneumatic apparatus. In this experiment, the acid is 
not decomposed ; it is the oxygen of the water with 
which the acid is diluted, that seizes upon and oxidizes 
the metal, and the hydrogen in the same portion of 
water being then disengaged, passes over in the state of 
gas. The hydrogen obtained by using zinc is the purest ; 
that obtained by using iron generally containing some 
carbon. 

The process just described is the readiest for obtaining 
this gas, but it is evolved in every instance in vv^hich 
metals are tarnished or rusted by moisture, and it may 
be obtained in great quantities, by causing the vapour 
of water to pass through an iron tube, or through a tube 
of any kind, containing a coil of iron wire, heated to 
ignition. The operation is generally conducted by the 



68 CHEMISTRY. 

use of a furnace, pi ovided with small holes opposite each 
other, to admit the tube to pass through it. 

Hydrogen, like oxygen and nitrogen, is invisible, elastic, 
and inodorous; but the last quality it seldom possesses, 
because it is very seldom perfectly dry, and when it con- 
tains water in solution, like alkaline sulphurets, its odour 
is considerably fetid. It generally contains half its weight* 
of water, and when it is received over water, ils volume 
is one-eighth larger than when received over mercury. 

Hydrogen gas is the lightest of all substances, except 
light and caloric. When pure, it is nearly 13 times 
lighter than common air. It is this extreme levity 
which occasions its utility for inflating balloons. 

Hydrogen gas is incapable of supporting life, but may 
be inhaled and exhaled a few moments without fatal 
effects ; it is returned by the lungs unaltered, and does 
not therefore appear to be positively noxious, but only 
operates by excluding oxygen. 

Although so currently called inflammable air, hydrogen 
gas is not capable of being burned, or of supporting 
combustion, unless oxygen be present. 

That water is in reality the union of oxygen and 
hydrogen, is proved not only by these gases being ob- 
tained by its decomposition, but by revei'sing the experi- 
ment and producing water from the gases themselves. 
Fifteen parts, by weight, of hydrogen, being mixed with 
85 parts of oxygen, and retained in a close vessel, if the 
hydrogen be fired by the electric spark, the gases will 
be converted into water, the weight of which will be 
equal to both the gases employed, and the gases disap- 
pear. 

The oil and resin of vegetables are derived from the 
decomposition of water ; and composts are partly bene- 
ficial as manures, from the hydrogen furnished in the 
process of putrefaction : if the compost be kept till this 
putrefaction is nearly over, its value is materially lessened 
as the hydrogen flies off 

Hydrogen combines with a larger quantity of oxygen 
than any other body ; its combustion, therefore, when 



HYDROGEN. 69 

mixed with oxygen, produces a more intense heat than 
any other combustion. This may be shown with a blad- 
der filled with oxygen, and another with hydrogen, by 
causing a stream from each bladder to pass through a 
tube upon a piece of ignited charcoal, or any other 
burning combustible. Each of the bladders should be 
furnished with a stop-cock, and as there is some risk of 
d violent explosion, bladders may be used with more 
propriety than any other vessels. 

Hydrogen is capable of combining with sulphur, phos- 
phorus, carbon, and arsenic ; and these compounds are 
respectively distinguished by the terms sulphuretted hy- 
drogen, phosphuretted hydrogen, carburetted hydrogen, 
and arseniated hydrogen. The flame which it yields in 
combustion is differently tinged, according to the sub- 
stance combined with it. Fireworks have been con- 
structed, in which the diversity of colour in the flame 
was produced by an attention to this property. 

Pit-coal, by distillation, aflbrds carburetted hydrogen, 
which is employed in what are called the gas lights. 
The coal thus distilled is not lost, but is converted into 
coke, which is as valuable as the coal from which it was 
produced. 

Sulphuretted hydrogen has an offensive smell, resem- 
bling rotten eggs. It is produced by dissolving the sul- 
phurets in acids: that disengaged by the sulphuric acid 
burns with a blue flame; that produced by the nitric 
acid burns with a yellowish white flame ; the latter acid 
disengages the largest quantity of the gas. 

Phosphuretted hydrogen, which has also a strong fetid, 
putrid smell, may be obtained by boiling in a retort a 
little phosphorus with a solution of potass. If this gas 
comes in contact with the air as it escapes from the re- 
tort, it takes fire, and a dense conical wTeath of smoke 
arises from it. It explodes if suddenly mixed with oxy- 
gen, oxymuriatic acid, or nitrous oxide gas. The ignis 
latuus, or jack-with-a-lantern, is attributed to this disen- 
gagement of the gas from the putrid effluvia common 
in swampy places where that phenomenon is observed. 



70 CHEMISTRY. 

Arseniated hydrogen may be obtained by adding sul- 
phuric acid, diluted with twice its weight of water, to 
four parts of granulated zinc and one of arsenic. Two 
parts of this gas, with one of oxygen, will explode loud- 
ly, and the products are water and arsenious acid. 

OF SULPHUR. 

Sulphur, or brimstone, is a well-known substance, of 
a yellow colour, brittle, moderately hard, devoid of smell, 
but not entirely so of taste. Its specific gravity is 1990. 
It is a non-conductor of electricity, and therefore becomes 
electric by friction. 

Sulphur is extremely disseminated, and is obtained 
abundantly, both in a state of purity, and from its com- 
binations with other substances. It flows from volcanoes, 
and is sublimed from the earth in some parts of Italy. 
It is combined more or less frequently with most ores, 
and is procured in large quantities from some of them, 
particularly those of iron and copper. In the Isle of 
Anglesea, it is sublimed from the copper ore, and collect- 
ed in large chambers, which are connected with the 
kilns by means of horizontal flues. 

Sulphur unites with most of the metals, rendering them 
brittle, and increasing their fusibility. It is soluble in 
oils, and by heat in alcohol, but water has no immediate 
action upon it. Hydrogen gas dissolves it, and is then 
called sulphuretted hydrogen. This gas is evolved dur- 
ing the putrefaction of animal substances. Sulphur 
unites with phosphorus by heat; but with charcoal it 
does not combine. 

If a bar of iron or steel, at a white heat, be rubbed 
with a roll of sulphur, the two bodies combine and drop 
down together in a fluid state, forming sulphuret of iron, 
a compound of the same kind as the native sulphuret of 
iron called pyrites, and which, from its abundance, sup- 
plies much sulphur. 

If potass or soda be melted by a moderate heat, with 
equal parts of sulphur, in a covered crucible, it forms a 



CARBON. 71 

substance, which, after cooling, is of a liver-brown col- 
our. These conDpounds are respectively called the 
sulphuret of potass or soda. 

Orpiment, or king's yellow, is a sulphuret ; it is com- 
posed of arsenic and sulphur. Vermilion is the red 
sulphuret of mercury. 

Sulphur sublimes at the heat of 170°, and is collected 
in the form of what is called Jlowers of sulphur. If 
heated to 185"^, it becomes very fluid, but by a continu- 
ance of the heat its fluidity diminishes, and it even be- 
comes thick ; on being allowed to cool, its former fluidity 
returns before it becomes solid. If as soon as the 
sulphur has begun to congeal, the inner liquid part be 
poured out, the internal cavity v.ill exhibit long needle- 
shaped crystals of an octahedral figure. 

Sulphur combines with oxygen in four definite propor- 
tions, forming an interesting class of acids, viz : the 
sulphurous, hypo-sulphurous, sulphuric, and hypo- 
sulphuric. From these combinations it is inferred that 
its prime equivalent is 2, and the -density of its vapour is 
I.lll, equal to that of oxygen. 

Sulphur is applied to many important uses. It is em- 
ployed in medicine, it enters into the composition of 
sulphuric acid, of gunpowder, and of the common com- 
position for paying the bottom of ships. Its fumes are 
employed in bleaching silk and wool, and checking the 
progress of vinous fermentation. Common matches, for 
lighting fires, are tipped with sulphur. 

OF CARBON. 

Vegetables, when burnt or distilled in close vessels, 
till their volatile parts are entirely separated, leave a 
black, brittle, and cinerous residuum, which constitutes 
the greater part of the woody fibre, and is called char- 
coal. Charcoal contains a portion of earthy and saline 
matters, but when entirely freed from these and other 
impurities, a solid, simple, combustible substance remains, 
which is called carbon. 



72 CHEMISTRY. 

Carbon exists naturally in a state of greater purity 
than it can be prepared by art. The diamond is pure 
carbon crystallized. The diamond, when pure, is colour- 
less and transparent. It is the hardest substance known ; 
and, as it sustains a considerable degree of heat un- 
changed, it was formerly supposed to be incombustible. 
It may, however, be consumed by a burning-glass, and 
even by the heat of a furnace. The difficulty of burn- 
ing it appears to arise from its hardness; for Morveau and 
Tennant have rendered common charcoal so hard by ex- 
posing it for some time to a violent fire in close vessels, 
that it endured a red heat without catching fire. Com- 
mon charcoal contains only 64 parts of diamond, or pure 
carbon, and 36 of oxygen in every 100. 

The common charcoal of commerce is usually pre- 
pared from young wood, which is piled up near the 
place where it is cut, in conical heaps, covered with 
earth, and burnt with the least possible access of air. 
When the fire is supposed to have penetrated to the cen- 
tre of the thickest pieces, it is extinguished by entirely 
closing the vents. When charcoal is wanted very pure, 
the product of this mode of preparing it will not suffice ; 
for the manufacturing of the best gunpowder, it is dis- 
tilled in iron cylinders. Chemists prepare it in small 
quantities, in a crucible covered with sand ; and, after 
they have thus prepared it they pound it, and wash away 
the salts it contains by muriatic acid ; the acid is removed 
by the plentiful use of water, and afterwards, the char- 
coal is exposed to a low red heat. Pure charcoal is per- 
fectly tasteless, and insoluble in water. 

Charcoal, newly prepared, absorbs moisture with 
avidity. It also absorbs oxygen, and other gases which 
are condensed in its pores, in quantity many times ex- 
ceeding its own bulk, and are given out unaltered. 
Fresh charcoal, allowed to cool without exposure to air, 
and the gas then admitted, will absorb 2.25 times its 
bulk of atmospheric air immediately, and .75 more in 
four or five hours; of oxygen gas, about 1.8 immediately, 
and slowly, 1 more ; of nitrogen gas, 1.65 immediately ; 



CARBON. 73 

of nitric oxide, 8.5 very slowly ; of hydrogen gas, about 
1.9 immediately; carbonic acid gas, 14.3 immediately. 
The greater part of these gases are expelled by a heat 
below 212°, and a portion even by immersing the char- 
coal in water. These absorptions are promoted by a 
low temperature ; but, at an elevated temperature, char- 
coal has such an afSnity for oxygen, that it will abstract 
it from almost all its combinations. Hence, its utility in 
reviving metals. 

Fossil coal, and all kinds of bitumen, contain a large 
quantity of carbon : it is also contained in oils, resins, 
sugar, and animal substances. 

Charcoal is one of the most unchangeable substances ; 
if the access of air be prevented, the most intense heats 
have no other effect than that just mentioned of harden- 
ing it, and rendering its colour a deeper black. Insolu- 
able in water, and incapable of putrefaction, it under- 
goes no change by mere exposure or age ; and stakes, 
and other materials of w^ood which have been charred, 
or superficially converted into charcoal, have been pre- 
served from decay for thousands of years ; the ancients 
availed themselves of this mode of preparing stakes which 
were to be driven into the ground for foundations and 
other purposes. 

The combinations of carbon with various substances, 
are called carburets. Steel is a combination of iron and 
carbon, in which the proportion of carbon is very small, 
only about a two hundredth part ; it is to its carbon that 
it owes its valuable property of admitting to be temper- 
ed. Cast-iron contains more carbon than steel, but this 
difference is not the only cause of the difference of the 
properties of iron in the two states; from its carbon, 
however, cast-iron admits of being made hard or soft, 
nearly in the same manner as steel. Plumbago contains 
90 parts of carbon, and but ten of iron ; it is from this 
excess of carbon, called a hyper-carburet of iron. The 
name of black lead, by which it is most generally known, 
is evidently improper, as it contains not a particle of 
lead. On the contrary, the connexion of plumbago with 
7 



74 CHEMISTRY. 

iron might be inferred from its resemblance in some 
respects to that kind of cast-iron which contains most 
carbon ; tlieir fracture is much alike ; and very fine 
filings of the iron tinge the hands . nearly in the same 
manner as the powdered plumbago. Yet cast-iron sel- 
dom contains more than a forty-fifth part of its weight 
of carbon. 

Charcoal possesses the singular property of combining 
with, and destroying the odour, colour, and taste, of va- 
rious substances. Putrid and stinking water may be 
rendered sweet by filtering it through charcoal-powder, 
or even by agitation wdth it. Common vinegar boiled 
with charcoal-powder, becomes perfectly limpid. Saline 
solutions that are tinged yellow or brown, are rendered 
colourless in the same way, so that they will afford white 
crystals. Malt spirit may be freed from its disagreeable 
flavour by distillation with about j}o of its weight of 
charcoal. Tainted vessels, after having been well scoured, 
may have every remaining taint removed by rinsing 
them with charcoal-powder ; and this powder will also 
restore the sweetness of flesh-meat but slightly tainted 
with putridity. As a dentrifice, charcoal in the state of 
an impalpable powder, is unrivalled, at once whitening 
the sound teeth, and sweetening the breath by neutrali- 
zing the fetor that arises from those which are carious, 
or from a scorbutic state of the gums. 

When charcoal is burnt in oxygen gas, nearly the 
whole of it disappears ; it is converted by its combina- 
tions with oxygen into an aeriform fluid, which, having 
the properties of an acid, is called carbonic acid gas. 
It contains 28 parts, by weight, of charcoal, and 72 of 
oxygen in every 100. It was discovered by Dr. Black, 
in 1755, and the discovery constitutes a memorable 
epoch in the history of chemistry, as it was attended 
with so clear a demonstration of the fact, that gaseous 
substances could become concrete, or form a part of solid 
substances, and that, on the contrary, solid substances 
could assume the gaseous form. 

Carbonic acid gas is nearly twice as heavy as atmo- 



CARBON. 75 

spheric air, and it may therefore be poured from one ves- 
sel to another, or retained in a cask and drawn off like 
other liquors. Though invisible, yet if contained in a 
glass, the presence of something different from, common 
air may be discovered by lighting a piece of paper, and 
putting it into a glass ; the light will instantly go out, 
and the smoke becoming entangled in this heavy gas, 
will show the quantity of the gas that may be present. 
The extinction of fire by this gas is instant and com- 
plete ; and when by any accident it is breathed, it pre- 
vents the power of speech, and rapidly destroys life. 
As it is evolved in the process of fermentation, it is often 
present in vats, and the public journals frequently record 
instances of persons who have incautiously descended 
into these vessels to clean them, perishing from its bane- 
ful effects in a few moments. 

Carbonic acid gas is always the result of the combus- 
tion of charcoal, which cannot be burnt in a close apart- 
ment, without imminent hazard of suffocation to the 
persons present. This gas is often contained in deep old 
wells, and places which have been long closed ; wherever 
it is suspected to exist, it will be proper to introduce a 
lighted candle, and if that burns as usual, no danger need 
be apprehended ; but if it be extinguished, it may be 
taken for granted that the air is unfit to breathe. A 
quantity of water, particularly if mixed with quick-lime, 
will, if thrown into a suspected place, absorb the car- 
bonic acid w^hich may be present. Carbonic acid gas 
constitutes what miners call choke-damp. 

Carbonic acid, though so deleterious when breathed, 
often forms a palatable wholesome ingredient in food, as 
it possesses the strongly antiseptic properties of carbon, its 
base. Hence the acid taste of Pyrmont, Spa, and other 
mineral waters ; hence the sparkling and agreeable brisk- 
ness of fermented liquors, such as beer, cider, &c. Yeast, 
from the large quantity it contains of it, has performed 
wonderful cures in putrid diseases. The atmosphere 
contains a very small quantity of this gas, the use of 
which may be to neutralize the putrid miasmata con- 



76 CHEMISTRY. 

tinually flying about. Water may by pressure be caus- 
ed to combine with nearly three times its own bulk of 
carbonic acid gas. 

The combinations of carbonic acid with other substan- 
ces, are called carbonates. Common chalk, lime-stone, 
and marbles, are all carbonates, and in their chemical 
composition differ but little from each other. Carbonic 
acid gas may be obtained from any of these, by putting 
them into a retort in powder, and pouring upon them a 
diluted acid, for example the sulphuric. The gas must 
be collected by the pneumatic apparatus. A cubical 
inch of marble contains as much carbonic acid, as, in the 
state of gas, would fill a vessel of six gallons- 

OF PHOSPHORUS. 

Phosphorus is a j'ellowish, transparent substance, of 
the consistence of wax. It is luminous in the dark at 
common temperatures, and at 67° it emits a white 
smoke. It is rapidly consumed at 122"^. It is preserved 
by keeping it in water : the water has, however, the 
effect of rendering it opaque ; and even exposure to light 
alters it in some degree. 

Phosphorus was originally prepared from urine, by a 
tedious and disagreeable process; but Gahn, a Swedish 
chemist, having discovered that it existed in bones, it is 
now prepared from this class of bodies. The bones are 
calcined till they cease to smoke, after which they are 
reduced to a fine powder. This powder is put into a 
glass vessel, and sulphuric acid is gradually poured upon 
it, till the further addition of acid occasions no extrica- 
tion of air bubbles. This mixture is largely diluted 
with water, well agitated, and kept hot for some hours; 
it is then filtered, and afterwards evaporated slowly, till 
a quantity of white powder falls to the bottom. This 
powder, by a second Alteration, is separated, and thrown 
away. The evaporation is then resumed ; and when- 
ever any white powder appears, the filteration must be 
repeated, in order to separate it. During the whole pro- 



PHOSPHORUS. 77 

cess, what remains on the filter must be washed with 
pure water, and this water added to the liquor. The 
evaporation is continued till all the moisture disappears, 
and nothing but a dry mass remaias. This mass is put 
into a crucible, and kept melted in the tire, till it ceases 
to yield a sulphurous smell ; it is then poured out. 
When cold, it resembles a brittle glass: it is pounded in 
a glass mortar, and mixed with one third, by weight, of 
charcoal dust. This mixture is put into an earthenware 
retort, to which is adapted a receiver, containing a little 
water. In a short time after the retort and its contents 
have become red-hot, the phosphorus passes into the re- 
ceiver, drop by drop. It is generally formed into small 
cylinders, by moulding it under lukewarm water, in 
glass tubes, or by putting a cork into the extremity of the 
pipe of a glass funnel, into which hot water may then be 
poured, and the phosphorus being dropt in, will mould 
itself From the remark made above, respecting the 
low temperature at which it burns, it is necessary to 
take great care that none of it adheres to the hand, 
especially under the nails, whence it would be with 
diiiiculty extracted ; as the heat of the body would kin- 
dle it, and it burns with extreme ardour. If, however, 
it be thoroughly mixed with several times its bulk of 
hog's lard, it may be held in the hand without injury. 

Phosphorus possesses a prodigious divisibility. A quar- 
ter of a grain being administered in some pills to a per- 
son who was afterwards opened, all the internal parts 
were found to be luminous, and even the hands of the 
person who opened the body had the same appearance. 

Phosphorus combines with oxygen, hydrogen, nitrogen, 
sulphur, most of the metals, and some of the earths. By 
combining with ojiygen, that is, after combustion, it 
forms phosphoric acid. When the phosphoric acid is 
combined with any substance, that substance is called a 
phosphate. The phosphorus in bones is in a state of 
phosphate of lime. The combination of phosphorus with 
iron forms that kind of iron called cold-short, which is 
brittle when cold, though malleable when heated, 
7# 



78 CHEMISTRY. 

Phosphorus, rubbed in a mortar with iron filings, takes 
fire immediately. Phosphoric match-bottles are pre^ 
pared by mixing orie part of flour of sulphur with eight 
of phosphorus. If a very small quantity of this mixture 
be taken out on the point of a match, and rubbed upon 
a cork, or any similar body, the match becomes lighted. 

At the temperature of 70*^ F., phosphorus combines 
with oil, and forms a compound, which, in contact with 
atmospheric air, becomes luminous in the dark. 

Put one part of phosphorus into six parts of good olive 
oil, or oil of cinnamon, which is preferable- Digest it in 
a gentle sand heat, until the phosphorus is dissolved, on 
which, immediately cork the bottle. If this oil be rubbed 
on any thing, it immediately becomes luminous in the 
dark, and yet has not sufficient heat to burn the sub- 
, stance. 

* . OF WATER. 

The composition of water has already been inciden- 
tally mentioned ; it consists of 85 parts of oxygen, and 
15 of hydrogen. It is a product of combustion, being 
formed whenever hydrogen is united to oxygen ; for these 
two bodies are not known to be capable of uniting in any 
proportion but that which forms water. The proofs of 
the composition of water are complete ; this fluid may 
be decomposed, that is, separated into the gases of which 
it is composed ; or the gases may be converted into water. 

Water is capable of existing in four difierent states, 
1. that of ice ; 2. that of water, or the liquid state ; 3. that 
of steam, or the gaseous state ; 4. in combination with 
crystals or other solids. 

I. Ice is the simplest state of water; if entirely de- 
prived of caloric, it would still be ice, only increasing in 
hardness as the caloric was abstracted. It is elastic, and 
when long kept much below the point at which it is 
formed, it becomes extremely hard. When pulverized, 
it is white. As one of the amusements of the court of 
Russia, in the severe winter of 1740, a palace was con- 
structed entirelv of ice hewn from the river Neva ; and 



WATER. 79 

a cannon made of the same materia], drove a hempen 
bullet through a board two inches thick at the distance 
of sixty paces. Water expands in passing to the state 
of ice, with a force that produces most astonishing 
effects; rending trees, and separating immense fragments, 
from the rocks and. mountains. This expansion is owing 
to the new arrangement of its particles ; the needles of 
the crystals crossing each other, either at angles of 60° 
or 120°. Ice is converted into water w^hen its tempera- 
ture is raised above 32°. 

2. Water retains its character as a fluid, at all tem- 
peratures betw^een 32° and 212°. It is employed as the 
standard of comparison in all tables of specific gravities. 

Water, when perfectly pure, possesses a high degree 
of transparency, and is entirely destitute of colour, taste, 
and smell. It is nearly inelastic, and consequently incom- 
pressible. It can only be obtained pure by distillation ; 
for as it is capable of holding a greater number of sub- 
stances in solution than any other fluid, the facility with 
which it becomes impregnated with foreign substances 
must be obvious. 

3. When water is converted into vapour, it combines 
with above five times the quantity of caloric w^hich would 
be required to bring ice-cold w^ater to the boiling heat ; 
it is estimated to fill a space 1800 times greater than in 
the state of water ; and the l^rge quantity of caloric 
with w^hich it is combined, is the only cause of the differ- 
ence. This refers to water under the common pressure 
of the atmosphere. When this pressure is lessened, as 
under an exhausted receiver, water assumes the state of 
vapour at a very gentle heat ; and when retained in a 
sufficiently strong vessel, as in Papin's digester, it may be 
rendered red-hot without being converted into steam. 
The elasticity of steam is prodigious ; and it increases 
with the heat at which the steam is formed. It has been 
found by experiments, that the expansive force of steam 
exceeds that of gunpowder. 

4. The singular tenacity with w^hich water is held 
by a great number of substances, is an interesting fact* 



80 CHE3IISTRY. 

Saussure has proved that alumine will retain one-tenth 
of its weight of water, at a heat which will keep iron in 
fusion; lime retains water with nearly the same force; 
and calcined plaster of Paris is changed from a state of 
powder to that of a solid, by combining with a large 
portion of water ; some salts, though tolerably hard and 
dry, are combined with as much water, as at a boiling 
heat would hold them in solution ; crystals owe their 
transparency, and even their solidity, to the water com- 
bined with them, for they lose both these properties as 
soon as the water is abstracted. By entering into many 
of these combinations, it is evident that water is deprived 
of a greater quantity of caloric than in a state of ice, 
and it is to this cause that we must attribute ita hardness 
in gems, 

MINERAL WATERS, 

The purest water which nature afibrds is melted 
snow, or of rain newly fallen, and collected in open 
fields, at a distance from houses, or contaminated atmo- 
sphere. The water of rivers and lakes is next in purity, 
especially where it is a rocky or gravelly bed. Stag- 
nant water, and that of marshes, is in general exceed- 
ingly impure, and often offensive to the taste, as it is 
largely impregnated with principles derived from the 
putrefaction of animal and vegetable matters. All these 
waters, however, possess the property called softness ; 
that is, they will dissolve soap. Spring waters are gene- 
rally hard : they will not dissolve soap ; and are, there- 
fore, unfit for any domestic purposes, and for n^anufac- 
turers. This arises from their containing earths and 
minerals in solution. Springs which supply water of a 
more agreeable taste than rain, river, or lake water, 
are the most abundant; and they always contain car- 
bonic acid. Other impregnations impair their taste; 
and, when they are in such access as to give a marked 
character to the water, the waters of such springs are 
called Mineral waters. 

It may often be important to obtain a general idea of 



MINERAL WATERS. 81 

the impregnations of a particular spring, in order to know 
whether it can be safely taken with food, or is likely to 
be useful as a medicine, or ought to be wholly rejected. 
We shall therefore give a short account of the tests, by 
which the most usual impregnations may be detected. 

The sensible qualities of water, such as transparency, 
colour, taste, and smell, should be examined, if possible, 
at the instant it comes from the spring. If the water 
must necessarily be examined at a distance, a bottle, 
with an air-tight stopper, should, at the fountain-head, 
be completely filled with it, in order to leave no space 
for air. The specific gravity should also be taken. To 
note exactly the sensible qualities of the water, will 
often indicate the re-agents which may be employed to 
denote its composition. 

Spring water generally contains more or less carbonic 
acid, which imparts an agreeable sparkling and brisk- 
ness; like that exhibited by fermented liquors. Where 
no colouring matter is present, the sparkling induces 
us to suppose this water more transparent than other 
waters. 

Carbonic acid sinks the taste of every other ingredient 
in waters ; and, therefore, such waters should not only 
be tasted at the spring, but some time after they have 
been exposed to the air, or after they have been boiled, 
as the carbonic acid will then have escaped. The tinc- 
ture of litmus will discover whether an acid is present 
in water, and as the carbonic is the only acid which is 
separated by exposure to the air, this exposure, if it 
deprive the water of the power of reddening litmus- 
paper or its solution, will show whether the acid is 
the carbonic or not. 

Water containing carbonic acid will hold a consider- 
able quantity of carbonate of lime in solution. Lime is 
detected most effectually by oxalic acid, which separates 
it from all its combinations, and forms with it an insolu- 
ble precipitate, unless an excess of acid be present, for 
then the precipitate wnll be re-dissolved. It is, therefore, 
best to use the oxalate of ammonia or potass, in order 
that the alkali may neutralize the acid in solution. 



82 CHEMISTRY. 

Diluted muriate of barytes will form a precipitate 
with water containing sulphuric acid. The precipitate 
is white, and insoluble in diluted muriatic acid. 

The nitrate of silver occasions a white precipitate or 
cloud in water containing muriatic acid. 

Alkalies held in solution, or alkaline or earthy carbo- 
nates, change paper stained with turmeric to a brown, 
or reddish brown, and light vegetable reds are rendered 
blue. The volatile alkali may be distinguished by its 
smell. Earthy and metallic carbonates are precipitated 
by boiling. 

Iron is very common in mineral w^aters ; it may be 
detected by its forming a purple or blackish precipitate 
with tincture of galls, or blue with prussiate of potass. 

Pure ammonia, or lime-water, precipitates magnesia 
and alumine, and no other earths, provided the carbonic 
acid has previously been separated by a fixed alkali and 
boiling. 

The mineral acids, when uncombined, give a perma- 
nent red to litmus paper, both before and after the water 
has been boiled ; whereas, the redness communicated by 
the carbonic acid gas goes off as the paper dries. 

Waters containing the sulphate of copper, may be de- 
tected by their giving the colour of copper to a polished 
plate of iron immersed in them. 

Sulphate of iron is precipitated by alcohol. 

The specific gravity of sea-water is generally 1.0289. 
It holds about ^V of its weight of muriate of soda in so- 
lution, with a small quantity of muriate of magnesia, and 
a still smaller proportion of the sulphate of lime^ At a 
distance from land, it is colourless and void of smell, but 
intensely saline and bitter. 

In analyzing waters with exactness, the gaseous pro- 
ducts they afibrd are carefully collected and examined. 

OF THE AIR. 

The atmosphere may be said in general terms to con- 
gist of oxygen and nitrogen ; but atmospheric air, even 



THE AIR. 83 

when purest, always contains a small proportion of other 
principles. Murray states its exact composition as follows : 

By measure. By weight. 

Nitrogen gas 77.5 75.55 

Oxygen gas 21.0 23.32 

Aqueous vapour - 1.42 1.03 

Carbonic acid gas .08 .10 

100.0 100.0 



As considerahle quantities of hydrogen escape from 
the earth, it might be presumed that it would be found 
in the atmospheric air, but as the atmospheric air has 
no chemical attraction for it in any proportion that can be 
detected, it probably escapes, by its levity, beyond the 
heights to which we have access. Dalton's experiments 
evince that the proportion of carbonic acid gas does not 
exceed a thousandth part, though a higher estimate is 
generally made. 

Atmospheric air is destitute of taste and smell, highly 
compressible, and perfectly elastic. It supports animal 
life, directly by the oxygen it affords to the lungs, where 
the blood combines chemically with it; and indirectly, 
by its mechanical properties in equalizing the tempera- 
ture of the globe, and preventing too rapid an evaporation 
of the moisture of the body. It is also not less necessary 
to vegetable life, as the vehicle for the distribution of 
water, and in its decompositions, by furnishing them with 
nitrogen, carbonic acid, and other principles. 

Atmospheric air contains the only proportion of oxy- 
gen which is subservient to the purposes of existence : 
all the known gases have been tried. None of them ex- 
cept the nitric oxide, can be breathed for even a few 
moments; and even the nitric oxide, during the short 
time which it remains on the lungs, produces a suspen- 
sion of the proper functions of the mind. In all the 
gases, also, combustion is either intemperate or wholly 
stopped. Notwithstanding the multiplied compositions 
and decompositions which are continually going on at 



84 CHEMISTRY. 

the surface of the earth, the due proportion of oxygen 
in the air is still maintained with a precision truly- 
astonishing. 

The specific gravity of the air is less, the greater the 
proportion of aqueous moisture which it contains. Hence, 
aeronauts find that their balloon sinks when passing over 
the sea, where the air is moister than over the land. 

OF GAS. 

This term is applied to all permanently elastic fluids, 
simple or compound, except the atmosphere, to which 
the term air is appropriated. 

Some of the gases exist in nature without the aid of 
art, and may, therefore, be collected ; others, on the con- 
trary, are only producible by artificial means. 

All gases are combinations of certain substances, re- 
duced to the gaseous form by the addition of caloric. It 
is, therefore, necessary to distinguish, in every gas, the 
matter of heat which acted the part of a solvent, and 
the substance which forms the basis of the gases. 

Gases are not contained in those substances from 
which we obtain them in a state of gas, but owe their 
formation to the expansive property of caloric. 

The formation of gases, — The different forms under 
which bodies appear, depend upon a certain quantity of 
caloric, chemically combined with them. The very for- 
mation of gases corroborates this truth. The production 
totally depends upon the combinations of the particular 
substances with caloric ; and though called permanently 
elastic, they are only so because we cannot so far reduce 
their temperature, as to dispose them to part with it; 
otherwise they would undoubtedly become fluid or solid. 

Water, for instance, is a solid substance in all degrees 
below 32° of Fahrenheit's scale ; above this temperature 
it combines with caloric, and it becomes a fluid. It 
retains its liquid state under the ordinary pressure of the 
atmosphere, till its temperature is augmented to 212°. 
It then combines with a larger portion of caloric, and is 



ALCOHOL. 85 

converted, apparently, into gas, or at least into elastic 
vapour ; in which state it would continue, if the tempe- 
rature of our atmosphere was above 212°. Gases are 
therefore solid substances, between the particles of which 
a repulsion is established by the quantity of caloric. 

But as in the gaseous w^ater or steam, the caloric is 
retained but with little force, on account of its quitting 
the water when the vapour is merely exposed to a lower 
temperature, w^e do not admit steam among the class of 
gases, or permanently elastic aeriform fluids. In gases, 
caloric is united by a very forcible affinity, and no dimi- 
nution of temperature, or increase of pressure, that has 
ever yet been efTected, can separate it from them. Thus 
the air of our atmosphere, in the most intense cold, or 
when very strongly compressed, still remains in the aeri- 
form state ; and hence is derived the essential characters 
of gases, namely, that they shall remain aeriform, under 
all variations of pressure and temperature, 

OF ALCOHOL. 

Alcohol, or the purely spiritous part of liquors which 
have undergone the vinous fermentation, and no other, 
is transparent and colourless like water ; its taste is high- 
ly pungent, but agreeable. It is extremely inflammable, 
and when set on fire it leaves no residuum. Its specific 
gravity is 0.800 ; and from its brightness and extreme 
fluidity, the bubbles which are formed on its surface, 
break with rapidity. It is not frozen even by the ex- 
treme cold of 65° ; but it has been frozen by the sudden 
abstraction of its caloric in the vacuum of an air-pump. 
In a vacuum, it boils at 56° ; in the air it is converted into 
vapour at 55°, and boils at 165°. It is from its being 
converted into vapour much sooner than water, that it 
is easily separated by distillation from wine, beer, and 
other liquors which contain it. All these liquors owe 
their strength to the quantity of alcohol they contain : 
the best port- wine contains about one-fourth of its bulk 
of alcohol. Brandy, rum, and whiskey, contain still more 
alcohol. Proof-spirit is half water and half alcohol. 
8 



86 CHEMISTRY. 

The alcohol obtained by distillation always contains 
some water, from which that operation will not free it ; 
to obtain pure alcohol, therefore, perfectly dry potass, 
obtained by exposing this alkali for some time to a red 
heat, is put into it : the water, having a stronger affinity 
for the potass than for the alcohol, combines with the 
alkali, which falls to the bottom, and the alcohol may be 
drawn off with the siphon. Afterwards the alcohol should 
be distilled with a gentle heat, and not quite to dryness, 
that any potass it may contain may be left behind. 

Alcohol mixes with water in all proportions, and the 
combination is so intimate that the mixture takes up less 
space than the fluids separately; and therefore, as ia 
every other combination where such an effect happens, 
caloric is extricated, and may be felt by the hand. 

Alcohol is the grand solvent for resins, and is much 
used for making varnishes. Camphor dissolves in it very 
readily, and the solution hastens that of some substances 
upon which the alcohol alone acts but slowly, or not at 
all, particularly copal. 

Alcohol takes up a small portion of phosphorus, which 
is precipitated by water. Quicklime alters the flavour 
of alcohol, and renders its colour yellow, though the 
earth in general, and metallic oxides, appear to have no 
action upon it. Both fixed and essential oils are soluble 
in alcohol. 

The composition of alcohol is not accurately known. 
The analysis of Lavoisier indicated that 100 parts of it 
contain of carbon, 30, of hydrogen, 7.5, and of water 
62.5 : but the accuracy of the analysis is doubtful ; for, 
as it was conducted by burning the alcohol in oxygen, 
part of the water may have been the produce of com- 
bustion, as Fourcroy and Vauquelin have clearly proved 
that alcohol contains oxygen. However this be, the 
manner in which the component parts of alcohol are 
united, remains entirely a mystery. 

Betancourt has ascertained the important fact, that 
the vapour of alcohol has more than double the expan- 
sive force of that of water of the same temperature, and 



ETHER. 87 

that the steam of alcohol, at 174"^, is equal to that of 
water at 212°. Hence, it has been suggested that alco- 
hol may be employed with advantage as the moving 
power of steam engines, with a great saving of fuel, and 
consequently, of expense, when means shall be contrived 
to save the fluid from being lost. 

OF ETHER. 

If alcohol be mixed with its own weight of sulphuric 
acid, gradually added, to prevent explosion, and the 
mixture be distilled in a sand bath, the first product ob- 
tained is alcohol, but afterwards a very different fluid, 
which is equal in quantity to half the alcohol employed. 
This fluid is called ether. 

Ether is still more inflammable and volatile than alco- 
hol, and equally as colourless. It is the lightest of all 
known fluids. Its smell is fragrant and agreeable, but 
not powerful. Its taste is hot and pungent. Its combus- 
tion yields a blue flame, and rather more smoke than 
alcohol. It boils at 98°. It may be obtained of the spe- 
cific gravity of .716. 

It is a valuable medicine ; being used externally for 
the headache or toothache, by pouring a little upon the 
hand and pressing it upon the forehead or cheek, till the 
pain it occasions goes off! Its internal use extends to all 
spasmodic affections. 

The nature of the change produced on alcohol by the 
acid, when ether is formed, is not well understood ; but 
it is supposed that ether contains a much larger propor- 
tion of hydrogen in proportion to its carbon. 

If the distillation of ether be continued till sulphurous 
vapours appear, and the recipient bl^ifhen changed, a 
new product is obtained ; it is called the sweet oil of 
wine, which is unctuous, thick, less volatile than ether, and 
of a yellow colour. The last product obtained by urging 
the fire, is sulphuric acid and acetous acid. 

Instead of the sulphuric acid, ether may be prepared 
with the nitric, the oxymuriatic, the acetic, and several 



88 CHEMISTRY. 

other acids. According to the acid employed, its proper- 
ties differ a little : nitric ether is often made, but the sul- 
phuric is the most common and the most valued. The 
peculiar properties of the ethers made with different 
acids, have not been minutely examined. 

Sulphuric ether acts upon most resinous substances; it 
is the best solvent of caoutchouc ; it dissolves also the 
essential oils and camphor ; mixes in all proportions with 
alcohol, but water only dissolves a tenth of it. It com- 
bines with caustic volatile alkali ; but not with the fixed 
alkalies or lime. It dissolves a little sulphur and phos- 
phorus. 

If the ether obtained emit a sulphurous odour, it must 
be purified by a second distillation, previous to which it 
should be mixed with a little potass, which will combine 
with the acid, and in part with the water. 

OF METALS. 

The metals, from their extensive and diversified 
utility, are amongst the most interesting classes of sub- 
stances existing. They are supposed to be simple bodies, 
and not a single fact has ever been ascertained which 
shows that they can be converted into each other; yet, 
to accomplish this, the alchemists exhausted their estates 
and their lives. 

The metals are distinguished by their possessing all or 
the greater part of the following properties ; hardness, 
tenacity, lustre, opacity, fusibility, malleability, and duc- 
tility ; and they are excellent conductors of caloric, elec- 
tricity, and galvanism. 

Metals are generally found in mountainous countries. 
They are somelmnes met with in a state of purity, 
and are then said to be found native: but they are 
mostly combined with other substances ; and, when com- 
bined in such quantities as to be worth separating, the 
substance is called an ore of the metal it contains. 

All the metals are susceptible of crystallization. The 
easiest mode of obtaining their crystalline form, is to let 



METALS. 



89 



out the middle part just after they have begun to con- 
geal ; the interior of the crust thus left assumes a crys- 
talline form. 

The metals are fusible at very different temperatures; 
mercury, for example, does not become solid, unless 
cooled down to 39°, and platina is not softened at the 
heat at which cast-iron runs like water. 

Metals differ from each other as much in hardness as 
in fusibility. Kirwan has adopted a very simple mode 
of showing their comparative hardness by figures. We 
shall adopt his plan, which he thus explains: 

3. Denotes the hardness of chalk. 

4. A superior hardness ; but yet what yields to the 
nail. 

5. What will not yield to the nail ; but easily, ancj 
without grittiness, to the knife. 

6. That which yields with more difficulty to the knife. 

7. That w^hich scarcely yields to the knife. 

8. That which cannot be scraped by a knife, but does 
not give fire with steel. 

9. That Vv^hich gives a few feeble sparks with steel. 

10. That which gives plentiful, lively sparks. 

Great specific gravity was formerly considered as one 
of the chief characteristics of the metals, the lightest 
metal being twice as heavy as the heaviest body of any 
other sort; but the discovery of several bodies, which 
possess all the characters of the metals, excepting weighty 
and which cannot therefore be omitted in the list of 
metals, has caused great specific gravity to be no longer 
distinctive. 

U a metal be exposed to a heat which will keep it in 
fusion, it may, without suffering any alteration but that 
of its figure, (which will adapt itself to the vessel,) be 
kept any length of time in that state, provided the access 
of air be kept entirely from its surface. But if the fusion 
be conducted in open vessels, the surface of the metal 
loses its metallic brilliancy; and if its apparent scuni be 
removed, another is soon formed, until the whole of the 
metal disappears, and instead of it we have an earthy 
8* ' ' 



90 CHEMISTRY. 

opaque powder which soils the hands. Upon collecting 
and weighing this powder, it is found to he heavier than 
the metal from which it was produced. This process 
was by the ancient chemists called calcination, and the 
product of it was called a calx ; they knew not the 
cause of it, and were, therefore, wholly unable to account 
for the increase of weight which they obtained by it ; 
but the moderns having thoroughly investigated the sub- 
ject, consider all metals as combustible bodies ; that in 
the operation just described the metal has suffered com- 
bustion, and that, therefore, the oxygen of the atmos- 
phere has combined with it, as it combines with all other 
bodies during combustion, and that it is solely from the 
oxygen absorbed that its additional weight is derived. In 
proof of this, they find by suitable experiments, that the 
oxygen absorbed is exactly equal to the weight acquired ; 
and also, that when the oxygen is taken away, by pre- 
senting some substance for which it has a greater affinity, 
the metal acquires all its original properties, and becomes 
of the same weight as at first. Hence for the vague 
term calx, the modern chemists used the word oocide, to 
denote the earth-like combinations of a metal with 
oxygen ; and the act or process in which this change 
takes place, is called oxidation* 

Oxygen will not combine with metals in all propor- 
tions, as acids will do with water, but only in one or two, 
or at most a few proportions. When the proportion 
of oxygen varies, the oxide of the same metal assumes 
different colours ; the colour is therefore selected to dis- 
tinguish these differences. Hence, we have the yellow 
oxide of lead, the red oxide of lead, &c. When the 
oxygen which converts a metal into an oxide is supplied 
by an acid, the name of the solvent, as well as the colour 
of the oxide, is sometimes given : thus we have the lohite 
oxide of lead by the acetous acid. 

Some of the metals are so much disposed to oxidation, 
that they became oxides at all temperatures. Iron is a 
metal of this description : the rust to which it changes in 
air or water is its red oxidei* 



METALS. 91 

If the oxide of a metal be exposed to a strong heat, it 
vitrifies, or is converted into a substance resembling com- 
mon glass. The substances employed for enamel paint- 
ing, for colouring gla«s, and for glazing earthenware, are 
mostly prepared from metallic oxides. 

If any of the malleable metals be hammered, its com- 
bined caloric becoming sensible, renders it hot, and 
passes off to surrounding bodies ; the metal at the same 
time is rendered denser, harder, more rigid, and in gene* 
ral more elastic. A portion of the caloric, to which, in 
comnnon with other bodies, metals owe their softness, 
appears to be driven out of it ; for its former state re- 
turns by heating it to ignition. Rolling produces tho 
same effect as hammering:. 

The metals combine with each other, and besides 
oxygen, with the simple substances, sulphur, carbon, and 
phosphorus. When two metals are combined together, 
the mixture is called an alloy of that metal whose weight 
predominates. 

Previous to the year 1730, only eleven metals were 
known, the list is now increased to forty-two chiefly by 
recent discoveries, and the probability is very strong, that 
there e:^ists a rnuch larger number* The metals may be 
divided into two classes ; — the malleable and the brittle ; 
the brittle metals may be further subdivided into those 
which are easily fused, and those which are fused with 
diflliculty. We shall enumerate them, in each of these 
classes, in the order of their specific gravity. 

1. Malleable Metals. 

1. Platina, 8. Copper, 

2. Gold, 9. Iron, 

3. Mercury, 10. Tin, 

4. Lead, 11. Zinc, 

5. Palladium, \2. Sodium, 

6. Silver, 13. Potassium. 

7. Nickel, 

2. Brittle Metals^ fused without difficulty. 

1. Bismuth, 3. Antimony, 

2. Arsenic, 4. Tellurium. 



4 



92 CHEMISTRY. 

Brittle Metahy of difficult fusion. 

1. Tungsten, 8. Titanium, 

2. Uranium, 9. Chromium, 

3. Rhodium, 10. Columbium, 

4. Cobalt, 1 1. Cerium, 

5. Molybdenum, 12, Osmium, 

6. Manganese, 13. Iridium. 



7. Tantalium, 



PLATINA. 



The specific gravity of platina, after hammering, 13 
23,000. It, therefore, holds the pre-eminence of all 
bodies in point of weight, and it has other extraordinary 
properties. 

It is incapable of tarnishing by exposure to the air. 
The strongest mineral acids have no effect upon it, if 
employed separately, nor will the strongest fire melt it, 
unless urged by oxygen gas ; a crucible of it not thicker 
than a sheet of paper, viiil endure the heat of the best 
furnace, and come out unaltered. When intensely heat- 
ed, it possesses, like iron, the property of welding, but 
the labour of working it is very great. Its hardness is 
7.5. Its colour is between that of iron^nd silver. 

Platina was unknown in Europe before the year 1741, 
w^hen a quantity of it was brought by Charles Wood, 
from Jamaica. It was supposed only to be found in the 
gold mines in Peru, but Vauquelin has met with it in 
Spain, in the mines of Guadalcanal. Its name, in the 
language of Peru, signifies little silver^ and on its great 
specific gravity being ascertained, attempts have been 
made to prevent its use, lest gold should be adulterated 
with it. It has never been met with except in the 
metallic state, in the form of smooth grains of all sizes 
up to that of a pea, but very seldom. la,rger. 

Platina may be fused by a powerful burning-glass; 
but its total infusibility by ordinary means, has caused 
various 'processes to be resorted to, for obtaining it in a 
solid, malleable state. For this purpose it must be dissol- 



PLATINA. • 93 

Ved in an acid,; oxymuriatic acid, and nitromuriatic acid 
both dissolve it. The latter acid should consist of one 
part of nitric, and three of muriatic acid. The solution 
is very corrosive, and tinges animal substances of a black- 
ish brown colour ; it affords crystals by evaporation. 
Count Moussin Pouschin directs malleable platina to be 
prepared from its solution as follows: Precipitate the 
platina by adding a solution of muriate of ammonia, and 
wash the precipitate with a little cold water. It is 
red-coloured, which distinguishes this metal from gold. 
Reduce it in a convenient crucible to the well-known 
spongy metallic texture, wash the mass obtained two or 
three times in boiling water, to carry off any portion of 
saline matter that may have escaped the action of the 
fire. Boil it in a glass vessel for about half an hour, in 
as much water mixed with one-tenth of muriatic acid, 
as will cover it about half an inch. This will carry off 
the iron that might exist in the metal. Decant the acid 
water, and edulcorate or strongly ignite the platina. To 
one part of this metal take two parts of mercury, and 
amalgamate in a glass or porphyry mortar. This amal- 
gamation takes plaAje very readily. The proper method 
of conducting it, is to take about two drachms of mercury 
to three of platina, and amalgamate them together, and 
to this amalgam may be added alternate small quantities 
of platina and mercury, till the whole of the two metals 
is combined. Several pounds may thus be amalgamated 
in a few hours, and in the large way, a mill might short- 
en the operation. As soon as the amalgam of mercury 
is made, compress it in tubes of wood, by the pressure of 
an iron screw upon a cylinder of wood adapted to the 
bore of the tube. This forces the superabundant mer- 
cury from the amalgam, and renders it sohd. After two 
or three hours, burn upon the coals, or in a crucible lined 
with charcoal, the sheath, in which the amalgam is con- 
tained, and urge the fire to a white heat ; after which 
the platina may be taken out in a very solid state, fit to 
be forged. 

The ductility of platina is such, that it has been drawn 



94 CHEMISTRY. 

into wire of less than the two-thousandth part of an inch 
in diameter. This wire admits of being flattened, and 
is stronger than that of gold or silver, of the same thick- 
ness. 

Platina will not combine with gold, except in a violent 
heat. When not more than one forty-seventh of the al- 
loy is platina, the gold is not perceptibly altered in colour; 
but, if the proportion be materially greater, the paleness 
of the gold betrays its impurity. Added in the proportion 
of one-twelfth to gold, it forms a yellowish-white metal, 
highly ductile, and so elastic, that Hatchett supposed it 
might be used for watch-springs, and other purposes. Its 
specific gravity was 19.013. 

It also requires a violent heat to make platina and 
silver combine; the silver becomes less white and duc- 
tile, but harder. If the two metals be kept for some 
time in fusion, they separate, and the platina, from its 
greater weight, sinks to the bottom. 

The alloy of copper and platina is hard, yet ductile, 
while the copper is in proportion of three or four parts 
to one. This alloy is not liable to tarnish, especially 
when the platina predominates ; and it is, therefore, ex- 
cellent for the specula of reflecting telescopes, as platina 
takes an excellent polish, and reflects a single image. 
The addition of a little arsenic improves this alloy. But 
copper is much improved in colour, grain, and suscepti- 
bility of polish, when the platina is only in proportion of 
a tenth or fifteenth. 

Alloys of platina with tin or lead are very apt to tar- 
nish ; that with lead is formed at the strongest heat : it 
is not ductile, and the lead is not absorbed by the cupel, 
unless it is in excess ; and even then, the separation of 
the lead is not complete. 

Platina unites easily with tin ; the alloy is very fusi- 
ble, bu^ its grain is coarse and brittle. It is ductile, 
when the proportion of tin is large: it becomes yellow 
by exposure to the air. ; 

Zinc renders platina more fusible, and forms with it a 
very hard alloy. The zinc cannot be entirely separated 
by heat. 



iVIETALS. 95 

Bismuth and antimony likewise facilitate the fusion 
of platina, with which they form brittle alloys, and are 
not wholly separated by heat. Arsenic has the same 
effect as these metals in promoting its fusion. 

Platina has not been united to forged iron ; but with 
cast iron, it forms an alloy which resists the file. 

If phosphorus be thrown upon red-hot platina, the 
metal is fused, and forms a phosphuret, which is of a 
silvery white, very brittle, and hard enough to strike 
fire with steel. As heat expels the phosphorus, Pollitier 
proposed this as an easy method of purifying platina ; 
but he afterwards found that the last portions of phos- 
phorus were retained by too strong an affinity. 

Several of the metallic salts decompose the solution 
of muriate of platina. Muriate of tin is so delicate a 
test of it, that a single drop, recently prepared, gives a 
bright red colour to muriate of platina, which before 
this addition, is so clear as to be scarcely distinguished 
from water. 

If nitro-muriatic solution of platina be precipitated by 
lime, and the precipitate digested in sulphuric acid, a sul- 
phate of platina will be formed. A sub-nitrate may be 
formed in the same way. 

Platina does not form a direct combination with sul- 
phur, but is soluble by the alkaline sulphurets, and pre- 
cipitated from its nitro-muriatic solution by sulphuretted 
hydrogen. 

The fixedness of platina admirably fits it for crucibles, 
and many other chemical utensils, which may be made 
thinner of this than of any other material whatever. 
It is, however, besides the disadvantages of its expense, 
liable to corrosion from caustic alkalies, and some of the 
neutral salts. 

If either be mixed and agitated with the nitro-muri- 
atic solution of platina, it takes up the metal ; and, as it 
will soon float on the surface of the solution, it may be 
poured off, and, if brushed over the clean surface of any 
other metal, it will soon evaporate, and impart to them 
a coating of platina. 



96 CHEMISTRY. 

GOLD. 

Gold is the most malleable, ductile, and most brilliant 
of all the metallic substances ; and, next to platina, the 
heaviest and most indestructible. 

Gold is seldom found except in the metallic state. It 
has been obtained in every quarter, and almost every 
country of the globe; but South America supplies a 
greater quantity than all the rest of the world. 

Many laborious experiments have been repeatedly 
made by able chemists, who appear to have established 
the fact, that gold exists in vegetables. 

A single grain of gold can be made to cover an area 
of more than 400 square inches; a wire of one-tenth of 
an inch in diameter wdll support a weight of 500 pounds ; 
and Dr. Blaclc has calculated that it would take fourteen 
millions of films of gold, such as cover some fine gilt 
wire, to make up the thickness of an inch ; whereas the 
same number of leaves of common writing paper would 
make up nearly three quarters of a mile. 

Though opacity is enumerated as one of the charac- 
ters of the metals, yet gold, when the 2 ooTrirth of an 
inch thick, which is about the thickness of ordinary gold 
leaf, transmits light of a lively bluish green colour. Per- 
haps all the other metals, if they could be equally 
extended, would show some degree of transparency, but 
none of them can be made so thin. 

The specific gravity of unhammered gold, is 19.258, 
and is increased but little by hammering. Its hardness 
is 6. It melts at 32°, of Wedgwood ; and if pure, its 
colour when in fusion is not yellow, but a beautiful 
bluish green, like the light which it transmits. 

Gold cannot be volatilized, except at an extreme heat 
The utmost power of Parker's celebrated burning lens, 
exerted upon it for some hours, did not cause it to lose 
any weight which could be discovered; but Lavoisier 
found that a piece of silver, held over gold melted by a 
fire maintained with oxygen gas, was sensibly gilt ; and 
perhaps the same delicate test would have shown its 
volatility by the lens. 



GOLD. 97 

After fusion, gold will assume the crystalline form. 
Tillet and Mongez obtained it in short quadrangular 
pyramidal crystals. 

Gold unites with most of the metals. Silver renders 
it pale ; when the proportion of silver is about one-fifth 
part, the alloy has a greenish hue. Silver separates 
from gold as from platina, if the alloy be kept for some 
time in fusion. 

Gold is strongly disposed to unite with mercury ; this 
alloy forms an amalgam, th'6 softness of which is in pro- 
portion to the quantity of mercury. It is by mercury, 
that in South America, gold is chiefly obtained from the 
earth with which it is mixed, and the gold is separated 
by distillation. This alloy readily crystallizes after fusion. 
It is applied by gilders to the surface of clean copper, 
and the mercury is driven off by heat. 

Gold unites freely with tin and lead, but both these 
metals impair its ductility. Of lead, one quarter of a 
grain to the ounce renders the gold brittle ; but tin has 
not so remarkable an effect. 

Copper increases the fusibility of gold, as well as its 
hardness, and deepens its colour. It forms the usual 
addition to gold for coin, plate, &c. The standard gold 
of Great Britain is twenty-two parts pure gold, and two 
parts copper; it is, therefore, called ** gold of twenty- 
two carats fire." 

Iron forms an alloy with gold, so hard as to be fit for 
edge tools. Its colour is grey, and it obeys the magnet. 

Arsenic, bismuth, nickel, manganese, zinc, and anti- 
mony, render gold white and brittle. When the alloy is 
with zinc in equal proportions, it has a fine grain, takes 
a high polish, and from these qualities, and its being not 
liable to tarnish, it forms a composition not unsuitable for 
the mirrors of telescopes. 

For the purpose of coin, Hatchett considers an alloy 
consisting of equal parts of silver and copper as the best, 
and copper alone as preferable to silver. The same dis- 
tinguished chemist gives the following order of different 
metals, arranged as they diminish the ductility of gold : 
9 



" 98 CHEMISTRY. 

viz. Bismuth, lead, antimony, arsenic, zinc, cobalt, manga- 
nese, nickel, tin, iron, platina, copper, silver. The first 
three were nearly equal in effect, but the platina was 
not quite pure. 

The nitric acid will take up a very minute quantity 
of gold, but the nitro-muriatic and oxy-muriatic acids 
are its only real solvents. The two latter acids are of a 
similar nature, and their effects on gold are increased by 
concentrating them, by enlarging the surface of the gold, 
and by the application of heat. The solution is of a 
yellow colour, caustic, and tinges the skin of a deep pur- 
ple. By evaporation it afibrds yellow crystals, which 
take the form of truncated octahedrons. These crystals 
are a muriate of gold ; they may be dissolved in water, 
and will stain the skin in the same manner as the acid. 

Most metallic substances precipitate gold from its solu- 
tion in the nitromuriatic acid : lead, iron, and silver, 
precipitate it of a deep and dull purple colour ; copper 
and iron throw it down in its metallic state ; bismuth, 
zinc, and mercury, likewise precipitate it. When pre- 
cipitated by tin, it forms the purple precipitate of Cassius^ 
which is much used by enamellers and manufacturers of 
porcelain. 

Ether, naphtha, and essential oils, take gold from its 
solvent, and from liquors which have been called potable 
gold, and are used in gilding. The gold obtained from 
these fluids by evaporation, is extremely pure. 

If diluted nitromuriatic solution of gold be used to 
write with upon any substance, and the letters while yet 
moist, be afterwards exposed to a stream of hydrogen gas, 
the gold will be revived, and the substance will appear 
gilt. Ribbons may be. gilt in this manner. Sulphurous 
acid gas revives the gold in the same manner. 

Lime and magnesia precipitate gold from its solution 
in the form of a yellowish powder. Alkalies do the same, 
but an excess of alkali re-dissolves the precipitate. The 
precipitate obtained by means of a fixed alkali appears 
to be a true oxide ; it is taken up by the sulphuric, nitric, 
and muriatic acids, but separates by standing with crys- 



GOLD. 99 

tallizing. The precipitate by gallic acid is of a reddish 
colour, and very soluble in the nitric acid, to which it 
comnnunicates a blue colour. 

Gold precipitated from its yellow solution by ammoniac, 
forms a powder ca.\\ed fulminating gold ; this dangerous 
compound detonates by friction, or a very gentle heat. 
It cannot be prepared or preserved without great risk. 
Macquer gives an instance of a person who lost both 
eyes by the bursting of a bottle containing some of it ; 
and which exploded by the friction of the glass-stopper 
against an unobserved grain of it in the neck of the 
bottle. 

Green sulphate of iron precipitates gold of a brown 
colour; but this soon changes to the colour of gold. 

The alkaline sulphurets precipitate gold from its solu- 
tion ; the alkali unites wdth the acid, and the gold falls 
down combined with the sulphur. The sulphur may be 
expelled by heat. 

The alkaline sulphurets will also dissolve gold. Thus, 
if equal parts of sulphur and potass, with one-eighth of 
their joint weight of gold in leaves, be fused together, 
the mixture, when poured out and pulverized, will dis- 
solve in hot water, to which it gives a yellowish green 
hue. Stahl wrote a dissertation to prove that Moses 
dissolved the golden calf in this manner. 

Sulphur alone has no effect on gold. The process 
called dry-parting is founded upon this circumstance. 
This is used for separating a small quantity of gold from 
a large quantity of silver. The alloy is fused, and flow- 
ers of sulphur are thrown upon its surface ; the sulphur 
reduces the greater part of the silver to a black scoria. 
The small remainder of the silver may now be separated 
by solution in nitric acid. The advantage of the opera- 
tion consists in saving the large quantity of nitric acid 
which would have been required to dissolve the silver of 
the alloy in its original state. 

The heat produced by the electro-galvanic discharge, 
reduces gold to the state of a purple oxide. 



100 CHEMISTRY. 

MERCURY. 

Mercury is distinguished from all other rnetals, by its 
fluidity at the common temperature of the atmosphere. 
Its colour is white, and its surface is like that of polished 
silver. Its specific gravity is 13.580; and it is, there- 
fore, the heaviest of all substances, except platina and 
gold. 

Mercury boils at 655; and does not cease to be a 
fluid, unless at or below the temperature of — 39^* In 
Russia, and Hudson's Bay, this temperature sometimes 
occurs naturally ; it may, however, be obtained by a 
freezing mixture. Mercury has then been examined, 
and found to be perfectly malleable, w^orking like soft 
tin. Experiments with artificial cold afford but few op- 
portunities for exhibiting this property ; but at Hudson's 
Bay, where surrounding objects were all equally cold, 
frozen mercury has been beaten upon an anvil into sheets 
as thin as paper. A mass of it, being thrown into a 
glass of warm water, became fluid, but the water was 
immediately frozen, and the glass shivered to pieces. 
To the touch, frozen mercury excites the same sensation 
as red-hot iron. 

Mercury is frequently obtained from the mines in the 
pure metallic state; sometimes it is combined with silver, 
but mostly with sulphur, in combination with which it 
is called cinnabar, when the mixture is of a red colour, 
but Ethiop's mineral, when it is black. These are both 
sulphurets of mercury. Mercury is supplied by many 
countries. The mines of Idria, in the circle of lower 
Austria, have been wrought for 300 years, and are esti- 
mated to yield 100 tons annually. From Spain, which 
supplies large quantities, it is exported to South America 
for amalgamating with gold ; for which use, the consump- 
tion is so prodigious, that the mine of Guanca Velica, 
in Peru, does not supply enough. This mine is a vast 
cavern, 170 fathoms in circumference, and 480 fathoms 
deep. 

Cinnabar, to obtain the metal from it, is mixed with 



MERCURY. 101 

quick-lime, and then submitted to heat. The lime com- 
bines with the sulphur, and the mercury which sublimes 
from the mixture is collected in receivers. Mercury sub- 
limes at the heat of 600^, and then has the appearance 
of a white smoke. In this state of vapour, its elasticity 
renders it capable of bursting the strongest vessels, if the 
attempt be made to resist its expansion. Distillation is 
the ordinary means of purifying mercury. 

Mercury combines very freely with gold, silver, lead, 
tin, bismuth, and zinc ; not so freely with copper, arse- 
nic, and antimony ; for iron, its affinity is extremely 
slight, and less so still, if possible, for platina. 

The alloy of mercury with any metal, if the mercury 
predominates so far as to render it soft, and of the con- 
sistence of butter, is called an amalgam. These amal- 
gams are much employed in silvering and gilding, as the 
mercury is easily driven off by heat, and the fixed metal 
is left behind. The metal with which the backs of 
looking-glasses are coated, is an amalgam of tin and 
mercury. 

The number of metals with which mercury combines, 
renders it extremely liable to adulteration. The union 
is in some cases so strong, that the baser metal will rise 
along with it in distillation. The experienced eye can, 
however, determine very small adulterations, by the want 
of perfect fluidity and brightness. Impure mercury also 
soils white paper, and the presence of lead may be 
detected by agitating the metal with water, by which 
means it will be oxidized. Or a very minute quantity 
of lead, present in a large quantity of mercury, may be 
detected by solution in nitric acid, and the addition of 
sulphuretted water. A dark brown precipitate will 
ensue, and will subside in the course of a few days. One 
part of lead may be thus separated from 15,263 parts of 
mercury. Bismuth is detected by pouring a nitric solu- 
tion, prepared without heat, into distilled water ; this 
metal will be separated in the form of a white precipi- 
tate. If tin be present, a weak solution of muriate of 
gold will cause a purple precipitate. 
9* 



102 CHEMISTRY. 

By agitating mercury for some time in oxygen or 
atmospheric air, a. part of it is converted into a black 
oxide. 

Most of the acids have more or less action on mercury. 
The sulphuric acid requires the assistance of heat, and 
sulphurous acid gas is disengaged during its action, and 
a white oxide is formed, which becomes yellow by pour- 
ing hot water upon it, and is then called turbith mineral ; 
it is a subsulphate of mercury ; the water holds in solu- 
tion sulphate of mercury. 

The nitric acid dissolves mercury rapidly without heat ; 
nitrous gas is disengaged, and the colour of the acid at 
the same time becomes green. If the acid be strong, it 
will take up its own weight of mercury in the cold, and 
will bear dilution ; heat will enable the acid to dissolve 
much more of the metal, and the addition of distilled 
w^ater will forn^ a precipitate, which is yellow if the 
water be hot, and white if it be cold. This, from its 
resemblance to the turbith mineral mentioned above, is 
called nitrous turbith. 

All the combinations of mercury with nitric acid are 
strongly caustic, and form a deep black or purple spot on 
the skin. When nitrate of mercury is exposed to a 
gradual and long continued low heat, it gives out a por- 
tion of nitric acid, and is converted into a bright red 
oxide ; this oxide retains a small portion of nitric acid ; 
it is called rxd precipitate, which is employed in medi- 
cine as a caustic. This red oxide parts with its oxygen 
simply by heat, and the mercury recovers its metallic 
state. The finest precipitate is made, by distilling the 
mercurial solution till no more vapour arises; then add- 
ing several successive portions of acid, and distilling it 
dry after each addition. The precipitate wuU thus be 
obtained in small crystals of a superb red colour. Red 
precipitate may be prepared by heat only : the mercury 
must for this purpose be kept at the heat of about 600^ 
for several months ; the red oxide thus formed was called 
precipitate per se. 

The acids, the alkalies, the earths, and most of the 



MERCURY. 103 

metals, precipitate mercury from its solution in the nitric 
acid. The precipitates by alkalies have the property of 
exploding, if triturated with one-sixth of their weight of 
flowers of sulphur, and afterwards gradually heated. 

The muriatic acid does not act on mercury, except by 
long digestion, which enables it to oxidize a part, and it 
dissolves the oxide. This acid, however, completely dis- 
solves the mercurial oxides, which, when nearly in the 
metallic state, or containing but little oxygen, form the 
muriate of mercury. When the oxy-muriatic acid is 
employed, the oxy-muriate of mercury, or corrosive sub- 
limate, is formed. Corrosive sublimate is highly caustic 
and poisonous. 

Sulphur readily combines with mercury. If triturated 
with this metal in a mortar, it forms with it a black sul- 
phuret, formerly called ethiop's mineral. This compound 
may also be formed by adding to sulphur in fusion one 
fourth of its weight of mercury. 

If ethiops mineral, or black sulphuret of mercury, be 
sublimed, it afibrds the red sulphuretted oxide, or artificial 
cinnabar. This cinnabar, when pounded and washed 
for painters' use, is called vermilion. To prepare it wdth 
accuracy, let 300 grains of mercury and 68 of sulphur, 
with a few drops of solution of potass to moisten them, 
be triturated in a porcelain mortar, wuth a glass pestle, 
till converted to the state of black oxide. Add to this 
160 grains of potass, dissolved in as much water. Heat 
the vessel containing the ingredients over the flame of 
a candle, and continue the trituration without inter- 
ruption during the heating. In proportion as the liquid 
evaporates, add clear water from time to time, so that 
the oxide may be constantly covered to the depth of 
near an inch. The trituration must be continued about 
two hours; at the end of which time the mixture begins 
to change from its original black colour to a brown, which 
usually happens when a large part of the fluid is evapo- 
rated. It then passes very rapidly to a red. No more 
water is then to be added, but the trituration is to be con- 
tinued without interruption. When the mass has acquired 



104 CHE3IISTRY. 

the consistence of a jelly, the red colour increases in 
brightness with surprising rapidity. The instant the 
colour has acquired its utniost beauty, the heat must be 
withdrawn, otherwise the red passes to a dirty brown. 
This is Kirchoff's method of preparing vermilion. Count 
Moussin Pouschin discovered that the brown colour may 
be prevented by taking the sulphuret from the fire as 
soon as it begins to be red, and placing it in a gentle heat, 
taking care to add a few drops of water, and to agitate 
the mixture from time to time. By this treatment an 
excellent red is obtained. 

Phosphorus, mixed with red oxide of mercury, and 
distilled, forms a phosphuret of mercury ^ which is of a 
black colour, and in the air exhales phosphoric vapours. 

PALLADIUM. 

Palladium is of a greyish white colour, scarcely dis- 
tinguishable from platina, and takes a good polish. It is 
ductile, and very malleable ; flexible, when reduced to 
thin slips, but not very elastic. Its fracture is fibrous, 
and in diverging striae, showing a kind of crystalline ar- 
rangement. It is harder than wrought iron« Its specific 
gravity is about 10.9, but may be increased by hammer- 
ing and rolling to 11.8. It is a less perfect conductor of 
caloric than the other metals, and less expansible, though 
in this respect it exceeds platina. 

Palladium was discovered by Dr. Wollaston in native 
platina. When exposed to a strong heat, its surface tar- 
nishes a little, and becomes blue ; but by increasing the 
heat, it becomes bright. By an intense heat, it is fused, 
but not oxidized. Its oxides, formed by means of acids, 
may be reduced by heat alone. 

Palladium may be obtained by adding to nitro-muri- 
atic solution of crude platina, a solution of prussiate of 
mercury, on which a flaky precipitate will gradually be 
formed, of a yellowish white colour. This is prussiate 
of palladium, from which the acid may be expelled by 
heat. 



PALLADIUM. 105 

The sulphuric, the nitric, and the muriatic acids dis- 
solve a small portion of palladium, and acquire by it a 
red colour. The nitro-muriatic dissolves it rapidly, and 
acquires a deep red. 

Alkalies and earths precipitate palladium from its so- 
lutions, generally of a fine orange colour ; an excess of 
alkali partly re-dissolves the precipitate. 

Alkalies act upon metallic palladium ; and this action 
is assisted by the contact of air. 

Green sulphate of iron precipitates palladium in a me- 
tallic state ; and all the metals, except gold, silver, and 
platina, do the same. Prussiate of mercury produces a 
yellowish white precipitate ; and, as it does not precipi- 
tate platina, it is an excellent test of palladium. 

Palladium forms with gold a grey alloy, harder than 
gold, less ductile than platina, and of a coarse-grained 
fracture. 

With an equal weight of platina, it resembles platina 
in colour and hardness ; but it is not so malleable, and 
melts at a heat a little higher than is requisite to fuse 
the palladium. The specific gravity of this alloy is 
15.141. 

With an equal weight of silver, the alloy is harder 
than silver, but softer than wrought-iron, and its polished 
surface resembles platina, except that it is rather whiter; 
specific gravity 1.29. 

Equal parts of palladium and copper, are a little more 
yellow, break more readily, assume somewhat of a lead- 
en hue when filed, and are harder than wrought iron. 
Specific gravity 10.392. 

Lead increases the fusibility of palladium, and forms 
with it an alloy of a grey colour, fine-grained fracture, 
harder than any of the preceding alloys, but very brittle. 

With tin, bismuth, iron, and arsenic, palladium forms 
brittle alloys : that with bismuth is very hard. 



106 CHEMISTRY. 

LEAD. 

The colour of lead is a bluish white; its specific 
gravity is 11.352 ; its hardness is 5 ; it is the softest, the 
least elastic and sonorous, of all metals used in the arts. 
It melts^ before ignition. It has scarcely any taste, but 
friction causes it to emit a peculiar smell. It stains paper 
and the fingers of a bluish black. 

Lead is very malleable, and therefore easily reduced 
to thin plates by the hammer; but hammering neither 
increases its specific gravity or hardness. Its ductility 
is not great ; a wire one-tenth of an inch in diameter, 
will support only 29:^ pounds. 

It is not certainly known that lead has ever been 
found in the metallic state ; the only lead ore that is ex- 
tensively found and worked, is a sulphuret of lead ; it is 
called galena, and is generally found in veins, both in 
siliceous and calcareous rocks. Lead ore frequently con- 
tains silver, and often antimony and bismuth. 

To obtain lead from galena, the galena is pulverized, 
and separated by washing from earthy admixtures; it is 
then roasted in a reverberating furnace, and afterwards 
melted in contact with charcoal. When the lead con- 
tains a quantity of silver w^orth extracting, it is fused in 
a strong fire, and the wind from a pair of bellows being 
directed over its surface, the whole of it is in succession 
converted into a yellow scaly substance called litharge, 
which being driven off as it forms, the silver is left at the 
bottom of the crucible. The litharge is a sub-carbonate 
of lead, and by fusing it vdth charcoal the lead is revived. 

When lead is fused in an open vessel, its surface 
quickly loses its lustre, and a scum appears, which is 
soon converted into a darkish grey powder. In the heat 
usually employed to melt lead, this grey powder or ox- 
ide sustains no further alteration ; but, if spread upon a 
suitable surface, and exposed to a low red heat, it be- 
comes successively whitish, yellow, and lastly, of a bright 
orange red. The yellow oxide is called by painters 
masticot ; the red they call minium, or merely red lead. 



LEAD. 107 

If the heat be urged much further, red lead is converted 
into litharge, which is a semi-vitreous substance ; that, by 
a little further heat, becomes a complete yellow glass, 
of so fusible a nature, as to penetrate and destroy the 
best crucibles. This glass enters into the composition of 
flint-glass. It promotes its fusibility, renders it heavier 
than other glass, better capable of bearing sudden 
changes of temperature, and from its greater softness, 
more suitable for cutting and polishing. 

When lead is exposed to the atmosphere, the bright- 
ness of its surface gradually diminishes, till it is nearly 
of the same colour as the grey oxide produced by heat. 
This oxide forms an even but a very superficial cover- 
ing, and it defends the metal from any further change. 

Most of the acids have an action on lead ; but for this 
purpose the sulphuric acid must be concentrated and 
boiling. Sulphurous acid gas escapes during the solution, 
and the acid is decomposed. By distilling the solution 
to dryness, a sulphate of lead is obtained : it is of a white 
colour, and affords crystals. This sulphate is caustic, and 
may be decomposed by lime and the alkalies. 

The nitric acid has a strong action upon lead, which, 
if concentrated, it converts into a white oxide ; but if di- 
luted, it dissolves the metal, and forms nitrate of lead, 
which is crystallizable. Lime, and the alkalies decom- 
pose the nitric solution. Nitrate of lead decrepitates in 
the fire, and is fused with a yellowish flame upon ignited 
coals. Sulphuric acid will take lead from the nitric 
acid, falling down upon being added to it, combined with 
the metallic oxide. The muriatic acid carries down 
the lead in the same manner, and forms a muriate of 
lead formerly called plumbum corneum. This is soluble 
in water. 

If the nitric acid, of the specific gravity of 1.260, be 
poured upon the red oxide of lead, 185 parts of the 
oxide are dissolved ; but 15 parts remain in the state of a 
deep brown powder. This powder is the brown oxide 
of lead : it contains 21 per cent, of oxygen. 

The muriatic acid, assisted by heat, dissolves a part 



108 CHEMISTRY. 

of the lead put into it, and oxidizes another part. The 
strong affinity of the oxides of lead for muriatic acid, 
causes them to decompose almost every substance in 
which this acid is found, by combining with it. Thus, 
when volatile alkali is obtained by distilling muriate of 
ammonia with the oxides of lead, the residuum is muriate 
of lead : the oxides of lead will even disengage the vola- 
tile alkali in the cold. Muriate of soda is decomposed 
if fused with litharge ; the lead uniting as in the last- 
mentioned case with the muriatic acid, and forming a 
yellow compound for the manufacture and use of which, 
as a pigment, a patent has been obtained. 

The acetous acid dissolves lead and its oxides. The 
white oxide of lead, known in commerce by the name 
of white lead, is prepared by its means. The lead is 
cast in thin plates, which are rolled up in the manner of 
a watch-spring, with a narrow space between each coil. 
They are then placed vertically in earthen pots, which 
contain a quantity of good vinegar, but their lower edge 
is prevented from coming in contact with the vinegar by 
suitable projections from the sides of the pots. The pots 
are then covered, and bedded in tan in a close apart- 
ment. The vapour of the acid slowly converts the sur- 
face of the lead into a white oxide, which is separated 
by shaking or uncoiling the plates. The plates are then 
re-submitted to the same process, until nearly consumed, 
when they are melted up, and cast over again. The 
white oxide thus obtained, is prepared for sale by wash- 
ing it in water, and drying it in the shade: it is then 
called indiscriminately white lead or ceruse, though some 
only give the name of ceruse to its mixture with chalk. 
If white lead be dissolved in acetous acid, it affords a 
crystallizable salt or acetate, which, from its sweet taste, 
is called sugar of lead. From its effect in diminishing 
acidity, sour wines have been sweetened by the addition 
of white lead, a practice which merits the severest repro- 
bation, as the oxides of lead are the most destructive 
poisons, in whatever way received into the animal sys- 
tem, whether in solution, by breathing the dust which 



SILVER. 109 

arises from them, or by working among them with the 
hands. 

The oxides of lead dissolve in oils, of which they cor- 
rect the rancidity, and, therefore, they have sometimes 
been added to the finer oils with fraudulent intentions. 
Linseed and other drying oils are rendered still more 
strongly desiccative by boiling upon oxide of lead. 

Pure alkaline solutions corrode lead, and dissolve a 
small quantity of it. 

Phosphoric acid, if heated with charcoal and lead, 
becomes converted into phosphorus, which combines 
with the metal. This phosphuret differs not much from 
common lead: it is malleable, and easily cut with a 
knife ; but it sooner loses its brilliancy than common lead ; 
and by fusion the phosphorus is burnt, aud the lead left 
pure. 

SILVER. 

Silver is the whitest of all metak, and next to gold, 
it is the most malleable and ductile. Under the ham- 
mer, the continuity of its parts is not destroyed, until its 
leaves are not more than the tf o!o o o of an inch thick ; 
and it may be drawn into wire finer than a human hair. 

The specific gravity of silver is 10.474 ; its hardness 
is 6.5. It continues melted at 28*^ of Wedgewood; but 
a greater heat is required to bring it info fusion. Its 
tenacity is such, that a wire of one-tenth of an inch in 
diameter, wdll sustain a weight of 270 pounds, without 
breaking. 

' Silver has neither smell nor taste. It is not altered 
by the contact of air, unless containing sulphurous va- 
pours ; but it may be volatilized by an intense heat, and 
Lavoisier oxidized it by the blow-pipe and oxygen gas. 
By exposing silver twenty times successively to the heat 
of a porcelain furnace, Macquer converted it into glass, 
of an olive-green colour. 

Silver is found, in greater or less abundance, in almost 
all countries which contain mines ; but the greatest quan- 
tities of it are obtained from the mines of Peru and 
10 



110 CHEMISTRY. 

Mexico. The celebrated mine of Potosi, which is situ- 
ated near the source of the Rio de la Plata, is one of the 
most considerable mountains of Peru; and this mountain 
is described by travellers as filled with veins of silver 
from the top to the bottom. 

Silver is often found native in ramifications consisting 
of octahedrons inserted in each other, also in small inter- 
winded threads, and in masses ; but it is most commonly- 
found in combination with sulphur. 

Silver forms alloys with most of the metals. Copper 
is the metal with which it is alloyed for the purpose of 
coinage. The British coinage contains 11 ounces 2 
pennyw^eights of fine silver in the pound troy. Copper 
stiffens silver, and increases its elasticity, but renders it 
less ductile. 

The alloy of silver and zinc is granulated on its sur- 
face, and very brittle. Tin, also, in the smallest quanti- 
ties, deprives silver of its malleability. Alloyed w^ith lead, 
silver ceases to be sonorous and elastic. 

Fine filings of silver, triturated with mercury in a 
warm mortar, form an amalgam, which by fusion and 
slow cooling, aflfords tetrahedral prismatic crystals, ter- 
minated by pyramids of the same form. The mercury 
cannot be separated from the silver, except by a much 
stronger heat than would be required to volatilize it 
alone. 

The sulphuric acid dissolves silver, if concentrated and 
boiling, and the metal in a state of minute division. The 
action of the muriatic acid upon silver is very trifling, 
unless oxygenized. 

The nitric acid, a little diluted, has a powerful action 
upon silver, of which it will dissolve half its weight. The 
solution is at first blue ; this colour disappears when the 
silver is pure ; but becomes green if it contains copper. 
If the silver contains gold, this metal separates in black- 
ish coloured flocks. The solution is extremely corrosive, 
and destructive to animal substances. When the acid is 
fully saturated, it deposits crystals as it cools, and also by 
evaporation. Those crystals are called lunar nitre, or 



SILVER. Ill 

nitrate of silver. By fusion, for which a gentle heat is 
sufficient, their water of crystallization is driven off; and 
also a part of the acid, by which they become a subni- 
trate ; this fornns the lapis infernalis, or lunar caustic 
of the surgeons ; it is of a black colour, and usually cast 
in the form of small sticks. A heat a little above what 
is necessary for fusing the nitrate, separates the whole 
of the acid, and the silver is revived. Lunar caustic 
should be made of silver entirely free from copper, as 
the copper is poisonous to wounds. 

The causticity of this and all other mineral solutions, 
is attributed to the strong propensity of the metal to 
assume the metallic state ; in consequence of which, it 
readily parts with its oxygen to substances it is in con- 
tact with ; and, therefore, such substances as are capa- 
ble of receiving the oxygen, virtually undergo a combus- 
tion. 

A solution of nitrate of silver in water, is perfectly 
free from colour ; but it stains the skin, and all animal 
and vegetable substances, an indelible black. It is 
employed, in a weak state, to dye the human hair, and 
when mixed with a little gum-water, forms a permanent 
ink for marking linen. It is employed for staining mar- 
ble and other stones. 

Nitrate of silver is a most powerful antiseptic ; a 
12,000th part of it dissolved in water will render the 
water incapable of putrefaction, and it may be separated 
at any time by adding some common salt. 

Silver is precipitated from its solution in nitric acid by 
muriatic acid, in the form of a white curd, v^^hich, when 
fused, forms a semi-transparent, and rather jfiexible mass, 
resembling horn ; it was therefore anciently called luna 
cornea or horn silver, and is supposed to have given rise 
to some of the accounts we have of flexible glass. It is 
a muriate of silver, soon blackens in the air, and is 
scarcely soluble in water. 

The muriatic acid does not dissolve silver, but has a 
strong affinity for its oxide, and as the muriate of silver 
is not very soluble in water, the nitrate of silver is em- 



112 CHEMISTRY. 

ployed as a re-agent, to discover the presence of muriatic 
acid in any liquid : for if it contains that acid, muriate of 
silver will fall down in a white cloud, on dropping nitrate 
of silver into it. 

The nitric acid sold in the stores generally contains 
muriatic or sulphuric acid, or both ; hence the nitrate of 
silver is employed to free the nitric acid from the two 
latter acids. For this purpose, nitrate of silver is poured 
into it by degrees, until no more precipitate is produced, 
after which it is rendered clear by filtering. Nitric acid 
thus purified, is called by artists precipitated aquafortis; 
but it still contains some silver, from which it cannot be 
freed except by distillation. 

When mercury is added to the nitric solution of silver, 
a precipitation of the silver is formed, which, from its 
resemblance to vegetation, is called arbor Diance, or tree 
of Diana. 

A few drops of nitrate of silver, laid upon glass, with 
a copper-wire in it, afford another beautiful precipitation 
of the silver, in the form of a plant. 

Silver supplies a fulminating powder, incomparably 
more dangerous than any other: the nitric solution of 
fine silver is precipitated by lime-water ; the w^ater is 
decanted ; and the oxide is exposed for two or three days 
to light and air. This dried oxide being mixed with 
ammonia, or volatile alkali, assumes the form of a black 
powder; decant the fluid, and leave the powder to dry 
in the open air. This powder is the fulminating silver, 
which, after having been once made, can no longer be 
touched ; it must therefore be left in the vessel in which 
the evaporation was performed. It should never be 
made but in minute quantities, and not more than the 
fulmination of a grain should be attempted at once. 

The avidity with which sulphur enters into combina- 
tion with silver, is instanced by Proust, in its tarnishing 
when exposed in churches, theatres, and other places, 
much frequented by men. This tarnish soon becomes 
a real crust, which, on examination, is found to be a sul- 
phuret of silver. It can only be detached by bending 



NICKEL. 113 

the silver, or breaking the silver to pieces, and its colour 
is a deep violet, like the sulphuret of silver formed by 
fusion. Proust is of opinion that sulphur is constantly 
fornned and exhaled by living bodies. 

The sulphuret of silver is brittle, and more fusible than 
silver. By a sufficient heat alone, the sulphur is vola- 
tilized, and the metal entirely recovered. 

NICKEL. 

Nickel is a metal of greyish white colour, between 
that of tin and silver; but when not pure, it is reddish, 
which is the colour of its ore. It is both ductile and 
malleable, when cold and red-hot. Its specific gravity 
is 9.000, and its hardness is 8. It is not fused at a less 
heat than 150° of Wedgwood, 

The ore of the nickel has been long known to the 
miners of Germany, where, from its resemblance to that 
of copper, it is called kupper-nickely or false copper. 
Bergman was the first who discovered that it contained 
a peculiar metal. 

Nickel is strongly attracted by the magnet, and at- 
tracts iron. On this account, it was supposed to contain 
iron ; but Chenevix and Richter discovered that a very 
small portion of arsenic prevents nickel from being affect- 
ed by the magnet. When it is not attractable, therefore, 
the presence of arsenic may be suspected. To separate 
arsenic from nickel, Chenevix boiled the compound in 
nitric acid, till the nickel was converted into an arse- 
niate, decomposed this by a nitrate of lead, and evapo- 
rated the liquor not quite to dryness. He then poured 
in alcohol, which dissolved only the nitrate of nickel. 
The alcohol being decanted and evaporated, he re-dis- 
solved the nitrate in water, and precipitated it by potass. 
The precipitate, well washed and dried, he reduced in 
a Hessian crucible, lined wuth lamp-black, and found it 
to be perfectly magnetic; but this property was de- 
stroyed again by alloying the metal with a small portion 
of arsenic. 
10=^ 



114 CHEMISTRY. 

The kiipfur-nickel of the Germans, is the sulphuret of 
nickel, and besides generally contains arsenic, iron, and 
cobalt. This ore is roasted, to drive off the sulphur and 
arsenic, then mixed with two parts of black flux, put 
into a crucible, covered with muriate of soda, and heated 
in a forge furnace. The metal thus obtained, which is 
still very impure, may be dissolved in diluted nitric acid, 
and then evaporated to dryness; after this process has 
been repeated three or four times, the residuum must be 
dissolved in a solution of ammonia perfectly free from 
carbonic acid. Being again evaporated to dryness, it is 
now to be well mixed with two or three parts of black 
flux, and exposed to a violent heat in a crucible, for half 
an hour or more. 

Richter says, that pure nickel is not liable to be 
altered by the atmosphere ; hence it is better adapted 
than steel for compass needles. 

By exposing nickel to heat with nitre, an oxide of it is 
obtained of a greenish colour, if the metal be impure ; 
but if otherwise, brown ; this oxide contains 33 parts in 
the 100 of oxygen. 

The French manufacturers of porcelain are said to 
use the oxide of nickel in producing a delicate grass 
green. A hyaeinthine colour may be given to flint-glass 
by the same oxide. 

Proust observes, that a certain proportion of nickel 
increases the whiteness of iron, diminishes its disposition 
to rust, and adds to its ductility. In Birmingham, it is 
occasionally combined with iron and brass. The Chinese, 
also, employ it in conjunction with copper and zinc for 
children's toys. It is the difficulty of working this metal, 
rather than its scarcity, that renders it so little known. 
Equal parts of copper and nickel form a red ductile 
alloy. The alloys of it with tin and zinc are brittle. 
Equal parts of silver and nickel forni a white ductile 
alloy. It does not amalgamate with mercury. Nickel 
is soluble with most of the acids, but the action of the 
sulphuric and muriatic is not considerable. The nitric 
and nitromuriatic acids are its proper solvents. The 



COPPER. 115 

nitric solution is of a tine green grass colour, and by- 
evaporation affords green crystals in rhomboidal cubes. 

Cronsted found that nickel combines with sulphur by- 
fusion, and that the result is hard and yellow, with small 
brilliant facets ; but the nickel which he employed was 
impure. 

j\ickel combines readily with phosphorus, either by- 
fusion along with phosphoric glass, or by dropping phos- 
phorus upon it while it is red-hot. The phosphuret of 
nickel is of a white colour, and when broken, exhibits 
the appearance of very slender prisms united together. 

It is remarkable that all those bodies called meteoric 
stones, which have at different" times fa^en from the 
atmosphere, contain nickel. 

COPPER. 

G)PPER is of a pale red colour, inclining to j^ellow. It 
has a styptic and unpleasant taste, and emits, by friction, 
a disagreeable smell. Its hardness is 8 ; its specific gra- 
vity is 7.788. In point of malleability, it is not much 
inferior to silver. It is sometimes found native. 

If copper be made red-hot, in contact with air, its sur- 
face rapidly oxidizes, and the oxide may be separated 
by the hammer, or by plunging the oxide into water. 
By the repetition of the process, another scale will be 
formed ; and this may be continued, till the whole of the 
metal disappears. These scales are a brown oxide of 
copper, which contains 84 parts of copper, and 16 of 
oxygen. This oxide may be converted into a brown 
glass, by a strong heat. 

When exposed to the air, copper becomes covered 
with a green crust, which is the green oxide of copper. 
This change takes place only at the surface, the oxide 
itsfelf forming a defence from further change. 

Filings of copper, thrown upon burning coals, burn 
with a greenish flame, and when the metal is kept in a 
greater heat than what is necessary for its fusion, it burns 
with a flanie of the same colour. 



116 CHEMISTRY. 

Most of the alloys of copper have been already no- 
ticed. This metal, with iron, forms the alderado, or 
Keir's patent metal for window-frames, designed to com- 
bine elegance with strength. Copper unites very readily 
with antimony, and forms an alloy, distinguished by a 
beautiful violet colour. 

Concentrated sulphuric acid dissolves copper by the 
assistance of heat, and the crystals of the solution, after 
adding water to it, form a sulphate of copper, generally 
called blue vitriol. If to this sulphate of copper be added 
a solution of arseniate of potass, a beautiful green pre- 
cipitate is formed, called Scheele^s green, or mineral 
green. Magnesia, lime, and the fixed alkalies, precipi- 
tate copper from its solution in sulphuric acid, in the form 
of an oxide. 

The muriatic acid does not dissolve copper, unless con- 
centrated and in a state of ebullition ; the solution is 
green ; the muriatic is caustic and astringent, fuses by a 
gentle heat, and congeals into a mass. 

The nitric acid attacks copper with effervescence. A 
large quantity of nitrous gas is disengaged. The acid 
first oxidizes the metal, and then dissolves the oxide. 
The solution has n blue cblour, much deeper than that 
by sulphuric acid, and affords crystals by slow evapora- 
tion. Lime precipitates the metal of a pale blue ; fixed 
alkalies, of a bluish white. Volatile alkali throws down 
bluish flocks, which are quickly re-dissolved, and produce 
a lively blue colour in the fluid. 

The acetous acid highly concentrated, dissolves copper; 
but when not concentrc).ted, it only corrodes the metal, 
and forms the oxide called verdigris. This oxide, dissolved 
in vinegar, forms a salt called by the chemists crystallized 
acetate of copper, and in commerce distilled verdigris. 

Copper is precipitated from its solution by iron. The 
iron is simply immersed in the solution ; the acid seizes 
upon it, and abandons the copper. The copper obtained 
by this means is called copper of cementation. Sulphate 
of copper is frequently found in streams of w^ater from 
copper mines; the quantity of salt which they contain is 



COPPER. 117 

not sufficient to reimburse the expense of evaporating 
the water to obtain blue vitriol ; but by throwing waste 
pieces of iron into them, the salt is decomposed, and the 
copper is precipitated in a metallic form, because the 
sulphuric acid has a greater attraction for iron than 
copper. It appears in effect as if the iron was changed 
into copper, and to the superficial observer favours the 
idea that metals are transmutable. The streams of 
mines thus containing sulphate of copper are often as 
valuable as the ore itself. 

All the salts of copper are poisonous ; and copper 
vessels should therefore never be used to contain any 
vehicle capable of holding the metal in solution. In 
Sweden, the use of copper vessels for culinary purposes, 
has been prohibited by law, and a statue of the metal 
dedicated to the man, at whose solicitation it was ob- 
tained. 

Sulphur combines with copper at a strong heat. 
Sulphuret of copper is brittle, softer than copper, of a 
black colour externally, and within of a leaden grey. 

A phosphuret of copper may be formed by casting 
phosphorus upon red-hot copper. It has the hardness of 
steel, but is too brittle and refractory to be useful. 

Prussic acid unites with the oxide of copper, and forms 
a brown pigment, superior, both in oil and water, accord- 
ing to the experience of Hatchet, to any other in use. 
It has a purple tinge, so as to form various shades of 
bloom or lilac when mixed with white, and which are 
not liable to fade as those made with lake. The best 
mode of preparing the prussiate of copper, is to dissolve 
the green muriate in ten parts of distilled water, and 
precipitate with prussiate of lime. 

Fixed alkalies have some action on copper, with which 
they form a light blue solution; the effect is greatest in 
the cold. 

Ammonia dissolves copper with much greater rapid- 
ity than fixed alkalies, whether it be in the state of 
metal or an oxide, and forms a beautiful blue solution. 
This solution, when recently made, is colourless if the 



118 CHEMISTRY. 

vessel be closed, but when the vessel is opened, the colour 
returns, gradually extending from the surface downwards. 
Oils appear to have no action on copper, until they 
become rancid, in which case their disengaged acid cor- 
rodes the copper, and the oil assumes a bluish green 
colour. 

IRON. 

Iron is of a bluish white colour, highly elastic, sonor- 
ous, has a styptic taste, emits a peculiar odour w^hen 
rubbed, and strikes fire with flint. In tenacity it exceeds 
all metals ; wire of it, only one-tenth of an inch in dia- 
meter, sustaining a weight of 450 pounds without break- 
ing. Its specific gravity is 7.788. 

Iron is less malleable than gold, silver, or copper; it 
is of all the metals in common use the most difficult of 
fusion, but the nearer it approaches to fusion, the more 
malleable and ductile it becomes. 

The hardness of iron, its great tenacity, the facility 
with which it may at a white heat be fashioned and 
welded, are the properties w^hich render it so valuable. 

Iron is attracted by the magnet or loadstone, and is 
itself capable of being rendered magnetic ; but this pro- 
perty, after having been communicated to it, is retained 
only a short time, unless it be in the state of hard steel. 

If suddenly plunged into cold water, while red-hot, it 
is rendered rather more rigid than before, but gradually 
cooling, renders it soft. 

Iron is sometimes found native. In the museum of the 
academy of science at Petersburgh, is a mass of native 
iron, 1200 tons in weight. 

Cast-iron is that which results from the fusion of the 
iron ore with charcoal : its peculiar properties are owing 
to its containing carbon, and other foreign matters. 

Steel is iron deprived of all impurities except a small 
portion of carbon : it is more ductile than iron, and a 
finer wire may be drawn from it than any other metal. 

Iron, united with about nine-tenths of charcoal, forms 
plumbago, or hyper-carburet of iron. 



IRON. 119 

Iron has a greater affinity for oxygen than oxygen has 
for hydrogen ; it therefore decomposes water by combin- 
ing with its oxygen ; which is the cause of its being easily 
altered by exposure to damp air or water. 

The action of air, assisted by heat, converts a thick 
pellicle of the surface of iron into a black oxide, contain- 
ing 25 per cent, of oxygen : and when this is hammered 
off, another is quickly formed. This black oxide is at- 
tracted in some degree by the magnet. If it be collected, 
and exposed to a strong heat under a muffle, it becomes 
a reddish brown oxide, containing 48 per cent, of oxy- 
gen. The yellow rust formed when iron is long exposed 
to damp air, is not a simple oxide, but contains a portion 
of carbonic acid. Proust only admits two stages in the 
oxidation of iron, viz. the green, and the brown, or red, 
and considers the other supposed oxides to be mixtures 
of these in various proportions. 

The green oxide may be obtained by dissolving iron 
in sulphuric acid, and then precipitating it by potass. 
This oxide contains 27 parts of oxygen, and 73 of iron, 
in the 100. By exposure to the air, it is converted into 
brown oxide, which contains 18 parts of oxygen, as ob- 
served above. 

G)ncentrated sulphuric acid scarcely acts on iron, un- 
less it be boiling ; but, if diluted with two or three times 
its weight of water, it attacks the metal immediately, 
and a strong efiervescence ensues, without any heat but 
that produced by the addition of the water. It is the 
hydrogen gas of the water which escapes, the oxygen 
being employed in oxidizing the metal ; which oxide the 
acid dissolves without being decomposed. If heat be ap- 
plied, more iron still is dissolved. This solution yields, 
by evaporation, sulphate of iron. The common green 
copperas of commerce is this salt in a state of impurity. 
It is much more soluble in hot than in cold water; and, 
therefore, a saturated solution of it in hot water affords 
crystals in cooling, as well as by evaporation. 

The substance called martial pyrites is a sulphuret 
of iron, and it is from the decomposition of it, that the 



120 CHEMISTRY. 

extensive demand for sulphate of iron is supplied. By- 
fusion with iron, sulphur produces a compound of the 
same nature as pyrites. 

The sulphuret of iron, as well as iron itself, burns 
rapidly, but without noise, w^hen triturated in a metallic 
mortar with hyper-oxymuriate of potass. This mixture, 
in a heap, if struck with steel, detonates strongly, and 
gives out a red flame. 

Sulphate of iron is decomposed by alkalies and by 
lime. Caustic fixed alkali precipitates the iron in deep 
green flocks, which are dissolved by the addition of more 
alkali, and form a red tincture. The mild alkali does 
not re-dissolve the precipitate it throws down, which is 
of a greenish'White colour. Distillation separates the 
acid from sulphate of iron, and leaves the brovniish-red 
oxide called colcothar. 

Astringent vegetables, such as gall-nuts, oak, tea, &c., 
precipitate a fine black fecula from sulphate of iron, and 
this precipitate remains suspended a considerable time in 
the fluid, by the addition of gum-arabic, and hence its 
utility as a writing ink. The well-known pigment called 
Prussian blue, is likewise a precipitate afforded by sul- 
phate of iron. 

Sulphur combines with iron merely by the assistance 
of water; thus, if flowers of sulphur be mixed with iron 
filings, and made into a paste with water, it soon becomes 
hot, swells, and emits the well-known smell of hydrogen, 
with watery vapours. The mixture takes fire, if in con- 
siderable quantity, even although buried in the earth. 
It is a composition, therefore, which may be used to form 
an artificial volcano* 

Concentrated nitric acid is rapidly decomposed by iron, 
a portion of the oxide of the acid oxidizes the iron, which 
oxide dissolves as it is formed, and the remainder of the 
acid passes off* in nitrous gas. The solution is of a red- 
dish brown, and deposits the oxide of iron after a certain 
time, particularly if exposed to the air. Diluted nitric 
acid affords a more permanent solution of iron, of a 
greenish, or sometimes of a yellow colour. Neither of 



jilRON. 121 

the solutions aflfords crystals, but both deposit the oxide 
of iron by boiling, at the same time that the fluid assumes 
a gelatinous appearance. This magma, by distillation, 
aflbrds fuming nitrous acid, much nitrous gas, and some 
nitrogen, a red oxide being left behind. 

Iron appears to be the only metal of which the solu- 
tions, or combinations with oxygen, are not of a noxious 
nature. The chalybeate waters form the best tonics 
which medicine possesses. 

The muriatic solution of iron, like all other solutions 
of the same metal, is decomposed by lime and alkalies ; 
but the precipitates are less altered, and may be easily 
reduced, especially such as are produced by the addition 
of caustic alkalies. Alkaline sulphupets, sulphuretted 
hydrogen gas, and astringents, also decompose this as 
well as the other solutions of iron. 

Water charged w^ith carbonic acid dissolves a con- 
siderable quantity of irpn. Vinegar appears to have 
httle or no effect upon iron, unless assisted by the air. 

If equal parts of iron chippings, and phosphoric glass, 
be melted together, a phosphuret of iron is obtained, 
which is very brittle, and has a whitish fracture. Iron, 
in its crude state, frequently contains phosphorus, which 
renders cast-iron very refractory, and forms the kind 
called cold-short iron, which is malleable when hot, 
though brittle when cold. 

Gold unites easily with iron, and becomes by this 
union harder and less malleable. In the proportion of 
six parts of gold and one of steel, the alloy may be 
beaten into plates without cracking. The iron is only 
partly separated by combustion in a glowing heat. Iron 
has a stronger attraction than gold for the oxy-muriatic 
and nitro-muriatic acids, and precipitates gold from these 
acids in its metallic state. 

Silver combines readily with iron. A mixture of 
fourteen parts of silver, and two and a half iron, is more 
elastic than silver, attracts the magnet, and is not decom- 
posed in a strong fire. A small portion of iron does not 
seem to injure the colour or malleability of the silver, 
11 



122 CHEMISTRY. 

Iron precipitates silver from all its solutions in acids ; but 
this happens in the nitric only, when the acid is not com- 
pletely saturated, or when nitrous gas is added. Muriate 
of silver is decomposed in the dry way by its distillation 
wdth iron filings. 

Iron precipitates mercury in its metallic state from its 
solution in acids. Distil with oxymuriate of mercury, 
the muriate is decomposed, and fluid mercury produced. 

Sulphate of iron precipitates mercury from its solution 
in nitric acid, in its metallic state. 

Lead is precipitated from its solutions in acids by iron. 
Iron also precipitates nickel from its acid solutions, and 
in the dry way takes from it the sulphur which it con- 
tains. 

Nickel has the strongest affinity for iron of all the 
metals, and is separated from it with the greatest difficul- 
ty. The alloy is fully as malleable, but less fusible than 
iron alone. Nickel is precipitated only in a very imper- 
fect manner by iron from its solutions in acids. 

Iron unites in close vessels with arsenic, which renders 
it more brittle, diminishes its attraction for^the magnet, 
and is separated from it with difficulty. 

When iron has been covered with tin, the tin appears 
to combine with it, and forms an alloy of greater depth 
than would readily be supposed ; even a white heat is 
insufficient to separate the tin entirely, yet till the w^hole 
of it is removed, the iron v;ill not weld, 

* TIN. 

Tin is a white metal, intermediate between that of 
lead and silver ; it has little elasticity ; its taste is dis- 
agreeable, and it has a peculiar smell, which increases 
by friction. Its hardness is 6 ; its specific gravity 7.291 ; 
is susceptible of very little increase by hammering. Its 
purity is judged of by its levity, as it cannot be alloyed 
with any metal lighter than itself. 

The malleability of tin is such, that it may be extend- 
ed into leaves not more than the 2000th part of an inch 



TIN. 



123 



thick ; the tin-leaf called tin-foil, is, however, twice this 
thickness. The tenacity of tin is but small ; a wire, one- 
tenth of an inch in diameter, will support only about 49 
pounds without breaking. Its flexibility is considerable ; 
it may be bent several times without breaking, emitting 
at the same time a distinct crackling noise. 

All the tin used in England is supplied by the mines 
of Cornwall, which furnish 3000 tons annually. Its ores 
occur most frequently in granite, but never in lime-stone. 
It is very rarely found native. 

Chaptal says, that if tin be kept in fusion in a lined 
crucible, and the surface be covered with a quantity of 
charcoal to prevent its calcination, the metal becomes 
whiter, more sonorous, and harder, provided the fire be 
kept up for eight or ten hours. 

The brilliant surface of polished tin soon becomes a 
little tarnished by exposure to the air, but the effect is 
very superficial and slight. 

Mercury dissolves tin with great facility, and in all 
proportions. To make this combination, heated mercury 
is poured on melted tin ; the consistence of the amalgam 
differs according to the relative proportions of the two 
metals. 

Nickel united to tin, forms a white and brilliant mass. 
Half a part of tin, melted with two parts of cobalt, and 
the same quantity of muriate of soda, furnished Beaume 
with an alloy in small close grains of a light violet 
colour. 

Equal parts of tin and bismuth, form a brittle alloy, 
of a medium colour between the two metals, and the 
fracture of which presents cubical facets. 

Zinc unites perfectly with tin, and produces a hard 
metal, of a close-grained fracture. Its ductility increases 
with the piroportion of tin. 

Antimony and tin form a white and brittle alloy, 
which is distinguished from other alloys of tin, by its pos- 
sessing a less specific gravity than either of the two met- 
als by which it is formed. 

In combining arsenic with tin, precaution must be 



124 CHEMISTRY. 

taken to prevent the arsenic from escaping by volatili- 
zation. Three parts of tin may be put into a retort 
with one-eighth part of arsenic in pow^der ; fit on a re- 
ceiver, and make the retort red-hot ; very little arsenic 
rises, and a metallic lump is found at the bottom, con- 
taining about one-fifteenth part of arsenic. It crystallizes 
in large facets, is very brittle, and hard to melt. 

If tin be kept in fusion, with access of air, its surface 
is speedily covered with a greyish pellicle, which is re- 
newed as fast as it is removed. If this grey oxide be 
pulverized and sifted, to separate the uncalcined tin, and 
calcined again for several hours under a muffle, it be- 
comes the yellow oxide of tin, called among artizans 
putty of tin, and extensively used in polishing glass, steel, 
and other hard bodies. 

A white oxide of tin is used in forming the opake kind 
of glass called enamel. This composition is made by 
calcining 100 parts of lead and 30 parts of tin in a fur- 
nace, and then fluxing these oxides with 100 parts of 
sand and 20 of potass. This enamel is white, and is 
coloured with metallic oxides. 

All the mineral acids dissolve tin, and it may be pre- 
cipitated from its solutions by potass; but an excess of 
potass will re-dissolve the metal. Nitro-muriate of gold 
is a test for tin in solution, with which it forms a fine 
purple precipitate. 

The sulphuric acid dissolves tin, whether concentrated 
or diluted with water. Part of the acid is decomposed, 
and flies off in the form of sulphurous acid gas. Heat 
accelerates the effect of the acid. Tin dissolved in sul- 
phuric acid is very caustic. 

The solution of tin in the nitric acid is performed 
with astonishing rapidity, and the metal is precipitated 
almost instantly in the form of a white oxiae. If this 
acid be loaded with all the tin it is capable of calcining, 
and the oxide be washed with a considerable quantity 
of distilled water, a salt may be obtained by evapora- 
tion, which detonates alone in a crucible well-heated, 
and burns with a white and thick flame, like that of 



tis. 125 

phosphorus. The nitric acid holds but a very small 
quantity of tin in solution, and when evaporated for the 
purpose of obtaining crystals, the dissolved portion quickly 
precipitates, and the acid remains nearly in a state of 
purity. Nitric acid, much diluted, holds rather more 
tin in solution, but lets it fall by standing, or by the ap- 
plication of heat. 

The muriatic acid dissolves tin, whether cold or hot, 
diluted or concentrated. If fuming and assisted by a 
gentle heat, the addition of the tin instantly causes it to 
Jose its colour and property of emitting fumes, and a 
slight effervescence takes place. The acid dissolves 
more than half its weight of tin ; the solution is yellow- 
ish, of a fetid smell, and affords no precipitate of oxide, 
like the sulphuric and nitric acids. 

The oxymuriatic acid dissolves tin very readily, and 
without effervescence, because the metal quickly absorbs 
the superabundant oxygen from the acid, and requires 
no decomposition of the w^ater to effect its oxidation. 

JVitro-muriatic acid, made with two parts of nitric acid 
and one of muriatic acid, dissolves tin with effervescence. 
It is the solution of tin in this acid which the dyers em- 
ploy to heighten the colour of their scarlet dyes. It is 
prepared by adding small portions of tin at a time to the 
common aquafortis of commerce ; when the appearance 
of oxide is observed at the bottom of the jar, muriate of 
soda is added, by which its solution is effected. If the 
colour imparted by this solution is not bright, a little 
nitrate of potass is added to it. 

The acetous, and most vegetable acids, have some 
action upon tin, particularly when aided by a gentle 
heat ; but the solutions thus obtained, are not used in the 
arts, 

Tin decomposes the corrosive muriate of mercury. It 
is for this purpose amalgamated with a small portion of 
mercury, and this amalgam being first triturated in a 
inortar with the corrosive muriate, the mixture is then 
distilled by a gentle heat. A colourless liquor first passes 
over, and is followed by a thick white vapour, which 
11 # 



126 CHEMISTRY. 

issues with a kind of explosion, and covers the internal 
surface of the receiver with a very thin crust. The 
vapour becomes condensed into a transparent liquor, 
which continually emits a thick, white, and very abun- 
dant fume. It was formerly called the fuming liquor of 
Libarius, and is the combination of the muriatic acid 
and tin. 

Tin has a strong affinity for sulphur ; the sulphuret of 
tin may be formed by fusing the two substances together; 
it is brittle, heavier than tin, and not fusible. It has a 
bluish colour, a lamellated texture, and is capable of 
crystallizing. 

The white oxide of tin combines with sulphur, and 
forms a compound called aurum musivum^ or mosaic 
gold, which is much used for giving plaster of Paris the 
resemblance of bronze, and improving the appearance 
of bronze itself. It is, also, occasionally used to increase 
the effects of electrical machines. Chaptal recommends 
for preparing it the process'of the Marquis de Bouillon, 
who directs an amalgam to be formed of eight ounces of 
tin and eight ounces of mercury. In forming the amal- 
gam, a copper mortar is heated, and the mercury poured 
into it, after which the tin is added in a state of fusion, 
and the mixture triturated till cold. Six ounces of sul- 
phur and four of muriate of ammonia, are then mixed, 
and the whole put into a matrass, which is to be placed 
in a sand-bath, and heated to such a degree as to cause 
a faint ignition in the bottom of the matrass. The fire 
must be kept up for three hours. The aurum musivum 
obtained by this process is usually excellent ; but if, 
instead of placing the matrass on the sand, it be imme- 
diately exposed upon the coals, and strongly and sudden- 
ly heated, the mixture will take fire, and a sublimate 
will be formed in the neck of the vessel, which consists 
of the most beautiful aurum musivum that can be pre- 
pared. 

The mercury and muriate of ammonia are not in 
strictness necessary to the production of aurum musivum. 
Eight ounces of tin dissolved in muriaLtic acid, precipi- 



ZINC. 127 

tated by the carbonate of soda, and mix^ with four 
ounces of sulphur, will produce a fine aurum musivum, 
but without the property of exciting electrical machines. 
A phosphuret of tin may be formed by melting in a 
crucible equal parts of tin and phosphoric glass, or by 
throwing small pieces of phosphorus into melted tin. The 
phosphuret of tin may be cut with a knife ; it extends 
under the hammer, but separates into laminae. When 
newly cut, it has the colour of silver ; its filings resemble 
those of lead, and the phosphorus takes fire when they 
are thrown upon burning coals. 

ZINC. 

ZI^'C is a bluish white metal ; its specific gravity is 
7.190; its hardness 6. It is distinguished by the singular 
property of being neither malleable nor ductile, at com- 
mon temperatures, but of acquiring both these qualities 
at the temperature of 210° to 300°. It has neither taste 
nor smell. It melts at the heat of about 700. 

Zinc, at a red heat, burns with a bright white flame, 
and throws out white flakes, called flowers of zinc. 
These flowers are the white oxide of the metal ; they 
are not volatile, but are merely driven off by the force 
of the combustion. They contain more oxygen than the 
grey oxide, which forms on the surface of the metal 
when it is heated to fusion. The white oxide of zinc 
may be converted into a yellow glass by a very violent 
heat. 

Zinc combines with most of the metals. With gold 
it combines in all proportions. The alloy is very hard 
and white when the metals are in equal proportions, and 
takes a fine polish, without being very liable to tarnish. 
One part of zinc is s^id to destroy the ductility of 100 
parts of gold. 

The alloy of silver and zinc is also brittle. Platina 
unites with zinc, and forms a brittle fusible alloy, toler- 
able hard, and of a bluish white colour, not so clear as 
that of zinc. 



128 CHEMISTRY. 

One part of zinc, and two and a half of mercurjr^ 
forni by fusion an amalgam which becomes solid. It is 
used to excite electrical machines. 

The well-known alloy called brass, which is formed 
of zinc and copper, is usually formed by cementing cop- 
per in a close crucible with calamine, an ore which con- 
tains zinc in the state of an oxide. 

Tin and zinc combine readily; the alloy is harder than 
tin: lead and zinc also form alloys which are harder than 
lead. Two parts of lead and three of zinc form a hard 
alloy, which bears hammering without extending. 

Iron and zinc have some affinity, as iron may be 
coated with zinc instead of tin, for culinary vessels. The 
solutions of zinc which may happen to be obtained, are 
not dangerous like those of lead. 

If water be thrown upon ignited zinc, a part of it is 
decomposed : the oxygen converts part of the metal into 
an oxide, and hydrogen gas escapes. 

Sulphuric acid dissolves zinc without heat.^ A salt 
may be obtained by evaporating the solution ; this salt, 
which is a sulphate of zinc, is known by the name of 
white vitriol ; it has a strong styptic taste. 

The nitric acid powerfully attacks zinc, and produces 
much heat ; and a great part of the acid is decomposed ; 
but crystals may be obtained by the slow evaporation of 
the residue. This salt, or nitrate of zinc, is deliques- 
cent ; it melts upon heated coals, and decrepitates, pro- 
ducing a slight reddish flame. If it be exposed to heat 
in a crucible, it emits red vapours, assumes the consis- 
tence of a jelly, and preserves this softness for a con- 
siderable time. The nitric solution of zinc is very 
caustic. 

Muriatic acid also acts strongly upon zinc, with the 
disengagement of much hydrogen gas. The solution, by 
evaporation, does not crystallize, but assumes the consist 
tence of a jelly, which if distilled, allows some of the 
acid to escape, and part of the muriate sublimes. 

Most of the metallic and vegetable acids dissolve zinc, 
which is precipitated from its solution by earths and al- 



POTASSIUM. 129 

kalies; the latter re-dissolves the precipitate, if added 
in excess. 

Sulphur cannot he. made to combine with metallic 
zinc ; but it combines readily with the oxide of zinc. 

Zinc may be combined with phosphorus by casting 
small pieces of phosphorus upon the melted metal, which 
should be covered with tallow or rosin to prevent its 
oxidation. Phosphuret of zinc is white, with a shade of 
bluish grey, has a metallic lustre, and is a little malleable. 

Zinc also combines with carbon, and forms a carburet 
of zinc. It generally contains a small portion of carbon. 

POTASSIUM. 

The fixed alkalies, potass and soda, are found not to 
be simple bodies, as had once been supposed, but oxides, 
each of them containing a peculiar metal in combination 
with oxygen. They were analyzed by Sir H. Davy, in 
a course of experiments which that distinguished chemist 
undertook with the express view of discovering their 
nature. He succeeded by means of the galvanic appa^ 
ratus in the following manner. 

In his first experiments he acted upon aqueous solutions 
of potass and soda, by a powerful voltaic combination, 
but in this way he only obtained the decomposition of 
the water of the solution. He then acted upon these 
alkalies in a state of igneous fusion. The potass was 
contained in a platina spoon, and was kept perfectly 
fused in a strong red heat, by means of a stream of 
oxygen gas, from a gasometer applied to the flame of a 
spirit-lamp. The spoon was preserved in communication 
with the positive side of the battery of the power of 100 
plates of 6 inches, highly charged, and the connection 
from the negative side was made by a platina wire. 
The advantage of this arrangement over the aqueous 
solution was soon apparent. The potass seemed to be a 
conductor in a high degree, and as long as the communi- 
cation was preserved, a most intense light was exhibited 
at the negative wire, and a column of flame, which 



130 CHEMISTRY. 

seemed to be owing to the development of combustible 
matter, arose from the point of contact. When the order 
was changed, so that the platina spoon was made nega- 
tive, a vivid and constant light appeared at the opposite 
point ; there was no effect of inflammation around it, but 
aeriform globules, which inflamed in the air, rose through 
the potass. 

As the products of the decomposition, which evidently 
appeared to have taken place in the above experiment, 
could not be collected, Sir H. Davy determined to apply 
the galvanic electricity to the alkali in its usual state. A 
small piece of potass, moistened a little by the breath, 
was placed upon an insulated disc of platina, connected 
with the negative side of a battery consisting of 100 
plates of 6 inches, and 150 of 4 inches square, in a state 
of intense activity, and a platina wire, communicating 
with the positive side, was brought in contact wath the 
upper surface of the alkali. The whole apparatus was 
in the open air. Under these circumstances, a vivid 
action was soon observed to take place. The potass 
began to fuse at both its points of electrization, and small 
globules, having a high metallic lustre, and precisely the 
same in characters to mercury, appeared, some of which 
burnt with explosion and bright flame. These globules 
are the basis of potass, which has received the name of 
potassium, and appears fully entitled to rank among the 
metals, as we shall proceed to show. 

It next became a matter of considerable diflSiculty to 
preserve and confine the basis of potass, in order to 
examine its properties. Sir H. Davy found, at length, 
that in recently distilled naphtha it may be preserved for 
some days, and that its physical properties may easily be 
examined in the atmosphere, when it is covered with a 
thin film of this liquid. 

Potassium, at the temperature of 60°, is only imper- 
fectly fluid ; at 70° it becomes more fluid ; at 100° its 
fluidity is perfect, so that different globules may easily 
be made to run into one. At 50° it becomes a soft and 
malleable solid, which has the lustre of polished silvery 



POTASSIUM. 131 

at about the freezing point of water, it beconies hard 
and brittle, and when broken in fragnaents, exhibits a 
crystallized texture, of a perfect whitencfss and high 
metallic splendour. To be converted into vapour, it 
requires a temperature approaching to that of a red 
heat. It is an excellent conductor of caloric and of 
electricity. 

Potassium will not sink in doubly distilled naphtha, 
the specific gravity of which is 770. Its specific gravity 
is to that of mercury as 10 to 223, which gives a pro- 
portion to that of water nearly as 6 to 10, so that it is 
the lightest fluid body known. Its levity is the physical 
property in which it differs most materially from the rest 
of the metals ; yet between the lightest and heaviest of 
the established metals, the difference is not much less, 
than between the lightest of the established metals and 
potassium. 

When potassium is introduced into oxymuriatic acid 
gas, it burns spontaneously, with a bright red light, and 
muriate of potass is formed. When thrown upon water, 
it decomposes with great violence ; an instantaneous ex- 
plosion is produced, with a brilliant flame, and a solution 
of pure potass is the result. When a globule is placed 
upon ice, not even the solid form of two substances can 
prevent their union ; for it instantly burns with a bright 
flame, and a deep hole is made in the ice which is found 
to contain a solution of potass. When a globule is 
dropped upon moistened turmeric paper, it instantly 
burns, and moves rapidly upon the paper, as if in search 
of moisture, leaving behind it a deep reddish-brown 
trace. 

So strong is the attraction of the basis of potass for 
oxygen, that it discovers and decomposes the small quan- 
tities of water contained in alcohol and ether, even w^hen 
they are carefully purified. 

When potassium is thrown into the mineral acids, it 
inflames, and burns on the surface. 

In sulphuric acid, sulphate of potass is formed ; in ni- 
trous acid, nitrous gas is disengaged, and nitrate of 



132 CHEMISTRY. 

potass is formed. When pressed upon a piece of phos- 
phorus, there is a considerable action ; the two sub- 
stances become fluid together, burn, and produce phos- 
phate of potass. 

When a globule of potassium is made to touch a. 
globule of mercury about twice as large, they combine, 
with considerable heat. The compound is fluid at the 
temperature of its formation, but when cool, it appears 
as a solid metal, similar in colour to silver. If this alloy 
be exposed to the air, it rapidly absorbs oxygen ; potass, 
w^hich deliquesces is formed, and in a few minutes the 
mercury is found pure and unaltered. When a globule 
of the amalgam is thrown into water, it rapidly decom- 
poses it with a hissing noise ; potass is formed, hydrogen 
disengaged, and the mercury remains free. 

The amalgam of potassium and mercury dissolved all 
the metals that were exposed to it ; and in this state of 
union mercury acts on iron and platina. 

Potassium combines with fusible metals, and the alloy 
has a higher point of fusion than the fusible metal. 

Potassium readily reduces the metallic oxides, when 
heated in contact with them. It decomposes common 
glass by a gentle heat, and at a red heat effects a change 
even in the purest glass. 

From a variety of experiments, Professor Davy con- 
cludes, that 100 parts of potass, consist of about 84 basis, 
and 16 oxygen. 

SODIUM, 

When soda is exposed to the action of galvanic 
electricity, in the same manner as the potass, in the 
experiment above stated, a metal is obtained which is the 
basis of the alkali, and is called sodium. 

Sodium is white, and opaque, and when examined 
under a film or naphtha, has the lustre and general ap- 
pearance of silver. It is exceedingly malleable, and is 
much softer than any of the common metallic substances, 
A globule of it only one-tenth of an inch in diameter, 
is easily spread over the surface of a quarter of an inch, 



SODIUM. 133 

and this property does not diminish when it is cooled to 
32° of Fahrenheit. 

By strong pressure, globules of sodium may be made 
to adhere and combine into one mass ; so that the prop- 
erty of welding, which belongs to iron and platina at a 
white heat only, is possessed by this substance at common 
temperatures. 

Sodium conducts caloric and electricity in a similar 
manner to potassium, and small globules of it inflame by 
the voltaic electrical spark, and burn with bright explo- 
sions. It is preserved under distilled naphtha in the 
same manner as potassium. 

Its specific gravity is smewhat less than that of water, 
being as .9348 to I. It is therefore heavier than potassi- 
um ; but the difference is so small, that we place them in 
the order in which they were discovered. 

Sodium has a much higher point of fusion than potas- 
sium: its parts begin to lose their cohesion at about 
120°, and it is a perfect fluid at about 180° ; so that it 
readily fuses under boiling naphtha. 

But, though so easily fiised, it remains in a state of ig- 
nition at the point of fusion of plate glass. 

The chemical phenomena of sodium are not very dif- 
ferent from those of potassium. When exposed to the 
atmosphere, it immediately tarnishes, and becomes 
covered with a white crust, which deliquesces much 
more slowly than that furnished by potassium. 

The flame that sodium produces in oxygen gas is 
white, and it sends forth bright sparks, occasioning a 
very beautiful effect. In common air, it burns with light 
of the colour of that produced during the combustion of 
charcoal, but much brighter. 

When introduced into oxymuriatic acid gas, it burns 
vividly, with numerous scintillations of a bright red 
colour. The substance produced by this combustion is 
muriate of soda, (common salt.) 

When thrown upon water, it produces a violent effer- 
vescence, with a loud hissing noise ; it combines with the 
oxygen of the water to form soda, and the hydrogen of 
12 



134 CHEMISTRY. 

the water is disengaged. This experiment exhibits no 
luminous appearance. With hot water, the decompo- 
sition is violent, and a few scintillations are observed at 
the surface of the fluid ; but this is owing to small par- 
ticles of sodium, which are thrown out of the water 
sufficiently heated to burn in passing through the at- 
mosphere. 

Sodium decomposes the water of alcohol and ether, in 
the same manner as the water in these fluids is decom- 
posed by potassium. 

It acts upon strong acids with great energy. With 
nitrous acid, a vivid inflammation is produced : with 
muriatic and sulphuric acids, there is much heat, but no 
Hght. 

Sodium, in its action upon sulphur, phosphorus, and 
the metals, scarcely differs from potassium. It com- 
bines with sulphur in close vessels filled with the vapour 
of naphtha, with a vivid light, heat, and often with ex- 
plosion. The sulphuret is of a deep grey colour. 

The phosphuret has the appearance of lead, and 
forms phosphate of soda by exposure to air, or by com- 
bustion. 

One-fortieth part of sodium renders mercury a fixed 
soda of the colour of silver, and the combination is 
attended with a considerable degree of heat. 

It makes an alloy with tin without changing its colour, 
and it acts upon lead and gold when heated. In its state 
of alloy, it is soon converted into soda by exposure to the 
air. 

Sir H. Davy concluded, that 100 parts of soda con- 
sist of 76 or 77 of sodium, and 24 or 23 oxygen. 

In concluding the communication to the Royal Society, 
from which the preceding view of the properties of 
potassium and sodium is derived. Sir H. Davy justly 
remarks, that an immense variety of objects of research 
is presented in the powers and aflinities of the new 
metals produced from the alkalies. In themselves they 
will undoubtedly prove powerful agents for analysis ; and 
having an affinity for oxygen stronger than any other 



BISMUTH. 135 

known substances, they may possibly supersede the appli- 
cation of electricity to some of the undecomposed bodies. 
In sciences kindred to chemistry, the knowledge of the 
nature of alkalies, and the analogies arising in con- 
sequence, will open many new views ; they may lead to 
the solution of many problems in geology, and show that 
agents may have operated, in the formation of rocks and 
earths which have not hitherto been suspected to exist 

BISMUTH. 

Bismuth is known among artisans by the name of 
tinglass. It is a metal of laminated texture, a pale 
yellowish red colour; not ductile or malleable, but 
reducible to powder under the hammer. Its specific 
gravity is 9.822 ; its hardness is 6. It melts at the heat 
of 460^. 

Bismuth sublimes when heated in close vessels ; when 
allowed to cool slowly, it crystallizes. It is not altered by 
water, and though it tarnishes by exposure to the air, it 
is not much changed. 

Bismuth combines with most of the metals ; its general 
effect is to increase their fusibility. The alloy of bis- 
muth and platina is very brittle. When exposed to the 
air, it assumes a purple, violet, or blue colour. The bis- 
muth may be separated by heat. 

Equal parts of bismuth and gold form a brittle alloy, 
not much paler than gold. 

Equal parts of bismuth and silver form a brittle alloy, 
but less so than the last. The specific gravity of this 
and the last alloy is greater than intermediate. 

The amalgam of mercury and bismuth is more fluid 
than mercury, and has the property of dissolving lead, 
without having its fluidity lessened. 

The alloy of copper and bismuth is not so red as 
copper. ^ 

A small portion of bismuth renders tin brighter, hard- 
er, and more sonorous : it is often therefore an ingredient 
in pewter. Bismuth remarkably increases the fusion of 



136 CHEMISTRY. 

this metal : when the alloy consists of equal parts, it 
melts at 280°. 

Bismuth does not combine with zinc, and its alloy with 
iron, cobalt, arsenic, and antimony, is unknown. 

The alloy of lead and bismuth is of a dark grey colour, 
a close grain, and very brittle. Eight parts of bismuth, 
five of lead, and three of tin, form a metal which melts 
at a heat not exceeding that of boiling water. Tea- 
spoons are made of this alloy, to surprise those unac- 
quainted wdth their nature : they have the appearance 
of common teaspoons, but are melted in hot water. 

Bismuth expands as it cools, for which reason it is well 
adapted for casting, and is sometimes added in the com- 
position for printers' types, particularly the smaller sizes, 
where a sharp perfect impression from the mould is of 
great importance. 

Bismuth may be used in cupellation instead of lead, 
and v/ould for this purpose be preferable to lead, were 
it not so much more scarce and expensive. 

This metal, when exposed to a red heat, burns with a 
faint blue flame, and emits yellowish fumes, which when 
condensed, form what are called flowers of bismuth. 
This oxide is converted into a greenish glass by strong 
heat. 

The sulphuric acid, when concentrated and boiling, 
has a slight action on bismuth. Sulphurous acid gas 
escapes, and part of the metal is converted into a white 
oxide. The sulphate of bismuth does not crystallize, 
and is very deliquescent. 

The nitric acid exerts a vehement action on bismuth. 
Much heat, with a large quantity of nitrous gas, is 
evolved. The solution, when saturated, affords crystals 
as it cools. This nitrate detonates weakly, and leaves a 
yellow oxide behind, which eifloresces in the air. 

The action of muriatic acid upon bismuth is very slow 
and inconsiderable ; and gven for this effect the acid 
must be highly concentrated. 

Water precipitates bismuth from all its solutions: the 
precipitate, which is a beautiful white, is when well- 



ARSENIC. 137 

Washed, used as a cosmetic, under the name of magis- 
tery of bismuth. It has, however, the disadvantage of 
turning to a dark colour, by a very sUght degree of sul- 
phurous effluvia ; and, as the metal resembles lead in 
its noxious qualities, and is seldom free from arsenic, like 
other mineral cosmetics, it cannot be used without dan- 
ger to the skin and the constitution. 

Magistery of bismuth is sometimes mixed with poma- 
tum, for the purpose of staining the hair of a dark 
colour. 

Sulphur combines readily with bismuth by fusion. 
The sulphuret of bismuth is of a bluish-grey colour, and 
crystallizes into beautiful tetrahedral needles. It con- 
tains 15 parts in 100 of sulphur. 

Phosphorus, dropped into melted bismuth, forms a phos- 
phuret of the metal, which only contains about 4 parts 
in the 100 of phosphorus, 

ARSENIC. 

Arsenic is of a brilliant bluish-white colour, a lami- 
nated texture, fusible, and very brittle. Its specific gra- 
vity is 8.310 ; its hardness, 7. It soon tarnishes by 
exposure to the air, becoming first yellowish, and then 
black ; but, if immersed in alcohol, its metallic lustre 
suffers no diminution. It is one of the most combustible 
metals, burns with a blue flame and the smell of garlic, 
and sublimes in a state of arsenious acid. It is, in all 
states, one of the most virulent poisons known. 

When exposed to the air, arsenic is gradually con- 
verted, by combining with oxygen, into a greyish-black 
substance, which is the grey oxide of arsenic. If this 
oxide be sublimed, the sublimate, having combined with 
an additional dose of oxygen, forms the white oxide of 
arsenic, which contains 7 parts in the 100 of oxygen. 
This oxide glitters as if it were powdered glass ; it has 
an acid taste, which terminates in an impression of sweet- 
ness: it has a smell like garlic. This is the state in 
which the arsenic of commerce is met with. 
12^ 



138 CHEMISTRY. 

The white oxide of arsenic may be converted into the 
metallic state by heating it with the oils, tallow, or char- 
coal, in close vessels ; but this is seldom necessary in the 
arts, as it enters into combination with other metals from 
the state of oxide. This oxide is soluble in 80 parts of 
water, at the temperature of 60*^, and in 15 parts of 
boiling water. When the solution is evaporated, the 
oxide crystallizes; and when heated to 283° it sublimes; 
if heated in close vessels, it becomes pellucid like glass, 
but soon recovers its former appearance by exposure to 
the air. The specific gravity of the glass is 5.000 ; of 
the white oxide 3.706. 

Almost the whole of the arsenic which is sold, is ob- 
tained from the cobalt ores of Saxony, where long winding 
flues are constructed, to the sides of which the sublimed 
arsenic attaches itself. 

Arsenic unites with most of the metals by fusion, and 
a very small quantity of it has often a material effect. 

Platina and arsenic form a brittle and fusible alloy; 
the arsenic may be driven oflf by a great heat 

Gold by fusion takes up about gV^h of arsenic, with 
which it forms a pale and brittle alloy. 

Silver takes up one-fourteenth of arsenic. 

Copper combines with five-sixths of arsenic, forming a 
white, hard, and brittle alloy ; when the quantity is small, 
it is both ductile and malleable ; it is called white tombac, 
?ind is much used in the manufacture of buttons. 

Iron is capable of combining with more than its own 
weight of arsenic ; the alloy is white, brittle, and capable 
of crystallization. 

The alloy of tin and arsenic is harder and more 
sonorous than tin, and has nearly the same external 
appearance as zinc. Tin often contains a sm9.ll quantity 
of arsenic. 

Lead takes up one-sixth of arsenic. The alloy is 
brittle and dark coloured. 

Zinc takes up one-fifth of arsenic, antimony one-eighth, 
gmd bismuth one-fifteenth. 

Upon the whole, the effect of arsenic is, to whiten the 



ARSENIC. 139 

red and dark coloured metals ; to give brittleness to the 
ductile ; to increase the fusibility of the refractory, and 
to render less fusible the rest. It is added to the com- 
positions of the mirrors of reflecting telescopes, to increase 
the density of the compound. 

The sulphuric acid, boiled on the oxide of arsenic, 
dissolves it; but the oxide precipitates as the solution 
cools. 

The nitric acid dissolves the oxide of arsenic, by the 
assistance of heat, and forms a deliquescent salt. 

The action of muriatic acid upon arsenic is very 
feeble, whether assisted by heat or in the cold. The 
sublimed muriate or butter of arsenic, is formed by mix- 
ing equal parts of the yellow oxide of arsenic, and corro- 
sive muriate of mercury, and distilling with a gentle 
heat ; in the receiver will be found a blackish corrosive 
liquor, which forms the sublimed muriate of arsenic. 

Potass, boiled on the oxide of arsenic, becomes brown, 
gradually thickens, and at last forms ^'hard brittle mass, 
which is deliquescent arsenical salt. Soda affords, by 
the same treatment, a product nearly similar. 

The combination of arsenic and sulphur is often found 
native, of a fine yellow colour ; it is then called orpi- 
ment ; this yellow sulphuret of arsenic may be prepared 
artificially, by mixing sulphur with the white oxide of 
arsenic, and heating them. It contains about 20 parts 
of arsenic in the 100. If a stronger heat be applied, so 
as to fuse this sulphuret, it assumes a scarlet colour, and 
forms the compound called realgar, which contains 80 
parts of arsenic in the 100. It is the red sulphuret of 
arsenic. Realgar is occasionally found native, as well as 
orpiment. Lime and the alkalies decompose these sul- 
phurets. 

The phosphuret of arsenic may be found by putting 
equal parts of phosphoret and arsenic into a sufficient 
quantity of water, and keeping the mixture moderately 
hot some time. It is black and brilliant, and ought to be 
preserved in water. 

The oxide of arsenic promotes the vitrification of 



140 CHEMISTRY. 

earths, but the glasses into which it enters are liable to 
tarnish. 

The workmen employed in the mines which produce 
arsenic, are subject to violent complaints, and premature 
death. When this deleterious mineral has been swal- 
lowed, the sulphuret of potass (liver of sulphur) dis- 
solved in water, is prescribed as the most effectual anti- 
dote. Arsenic, whether alone or in a mixture, may be 
distinguished by throwing it upon burning coals; as it 
will afford white fumes and the smell of garlic. 

ANTIMONY. 

Antimony is a brittle metal, of a white colour, inclin- 
ing to grey, a laminated texture, exceedingly brittle, and 
neither malleable nor ductile. It may be reduced to 
powder. It has some taste, but no smell. Its specific 
gravity is 6.860 ; its hardness, G.5. It tarnishes but little 
by the action of tk^ air or w^ater. It melts at a low red 
heat, or 809^ ; and, if the heat be much increased, it is 
volatilized in white fumes. This white oxide of anti- 
mony was formerly called argentine snow, or Jlowers of 
aritmony. 

If antimony he brought to a white heat, and then 
shaken, it takes fire, with a kind of explosion. If fused 
on charcoal before the blow-pipe, and thrown into the 
air, it divides into globules, and burns with a brilliant 
white light as it falls to the ground. 

The antimony of commerce is found in two states — 
that of crude antimony, and in the metallic state. Crude 
antimony is the sulphuret of this metal, and is the only 
ore of it which is obtained in sufficient quantity to be 
wrought. Metallic antimony, better known by the name 
of regulus, is crude antimony deprived of its sulphur. 
If iron filings be fused with crude antimony, they com- 
bine with its sulphur, and the antimony is obtained pure. 
One-fifth of iron will combine with all the sulphur by 
which this metal is mineralized. In the large way, an- 
timony is obtained by melting calcined antimony with 



ANTIMONY. 141 

dried wine-lees, in a reverberatory furnace, and the sul- 
phur is often not wholly removed from it. Sulphuret of 
antimony contains 26 parts in the 100 of the metal. 

Antimony will enter into combination with most of 
the metals. With platina, it affords a brittle alloy, which 
is much lighter than platina. The platina cannot after- 
wards be separated from it by heat. 

Gold may be combined w^th antimony, by fusing them 
together ; and the antimony may be separated by an in- 
tense heat. 

Silver and antimony form a brittle alloy, the specific 
gravity of which is greater than intermediate between 
the specific gravities of the two metals. 

Mercury does not combine freely with antimony. Gel- 
lert succeeded by using hot mercury, and covering the 
whole with water. 

Equal parts of lead and antimony, form a porous and 
brittle alloy ; three parts of lead and one of antimony is 
the best composition for printing-types; and of all the 
alloys of antimony is the most useful. It forms a hard 
alloy, scarcely malleable, but so brittle as to break with- 
out bending, unless in very slender pieces ; when pro- 
perly prepared, its fracture has the appearance of that 
of cast-steel. In fusing the two metals, the antimony 
should be well mixed by stirring, as from its levity it 
will float on the lead ; if the mixture has not been com- 
plete, the alloy breaks with brilliant facets. This alloy 
is more fusible and fluid than either of the metals sepa- 
rately, and as antimony expands in cooling, it takes a 
sharp impression of a mould. Bismuth is sometimes 
added to increase this property, as w^ell as the fusibility; 
but this metal is too costly to be added in any useful pro- 
portion, except for the smallest types. The antimony 
should be completely freed from sulphur, otherwise the 
types made of it undergo a spontaneous decomposition, 
easily break, and are covered with a black crust. 

Twelve parts of lead and one of antimony, form an 
alloy very malleable ; yet much harder than lead ; 16 
parts of lead and one of antimony, form an alloy which 
does not differ from lead, except in being rather harder. 



142 CHEMISTHY. 

G)pper combines readily with antimony; the colour of 
the alloy is a beautiful violet, and its specific gravity is 
greater than intermediate. 

The alloy formed by iron and antimony is brittle and 
hard ; its specific gravity is less than intermediate. The 
disposition of iron to receive magnetism, is much im- 
paired by antimony. 

The alloy of tin and antimony is harder than tin, 
white, and brittle : the specific gravity is less than inter- 
mediate, yet the combination is so intimate, that it is 
scarcely possible to separate the antimony from the tin. 
A small portion of antimony is added with tin to form 
pewter. 

Le Sage analyzed some nails intended for ship-build- 
ing, and found them to consist three parts tin, two of 
lead, and one of antimony. These nails could be made 
to penetrate oak boards, and were not acted upon by 
sea-water. 

The alloy of zinc and antimony is brittle. 

Pure pewter has some action upon antimony, for it 
becomes purgative by standing in a vessel made of this 
metal. 

Sulphuric acid, boiled upon antimony, is slowly de- 
composed. Sulphurous gas escapes, and sulphur, itself, 
by continuing the process. The sulphate of antimony is 
deliquescent, and decomposed by the fire. 

The nitric acid is decomposed by antimony very readi- 
ly ; a considerable part of the antimony is oxidized, and 
part of the oxide is dissolved. This oxide is very white, 
and difficult of reduction. 

The muriatic acid acts freely upon antimony, except 
by long digestion. The muriate of antimony, obtained 
by evaporation, is very deliquescent : it is fusible in the 
fire, and volatile. 

Two parts of corrosive muriate of mercury, and one 
of the muriate of antimony, distilled by a gentle heat, 
aflbrd the common butter of antimony, or sublimed mu- 
riate of antimony. This preparation is fluid at a gen- 
tle heat ; by plunging the vessel which contains it into 
hot water, it becomes sufficiently fluid to pour out. . 



ANTIMONY. 143 

When butter of antimony is dropped into water, part 
of the metal, in the form of an oxide, is thrown down in 
a white powder. This substance is called powder of 
algaroth, which acts as a strong purgative. 

If sulphuret of antimony be melted, and the heat con- 
tinued, the sulphur sublimes, and the antimony is con- 
verted into a grey oxide ; this oxide may likewise be 
obtained by powdering metallic antimony, and then 
submitting it lo calcination. The oxide will combine 
with y^o of sulphur, and this compound forms, by fusion, 
a glass called the glass of antimony. 

Antimony supplies medicine with some of the most 
active and valuable remedies. The acid of tartar forms 
with it the preparation called emetic tartar, the new 
name of which is antimoniated tartrate of potass : it is 
composed of 56 parts tartrate of antimony, 36 tartrate 
of potass, and 8 of water. 

The alkalies and lime decompose the antimoniated 
tartrate of potass. 

The alkalies alone have no perceptible action on anti- 
mony, but the alkaline sulphurets dissolve it completely. 
Kermes' mineral, a medicine formerly of great celebrity, 
is a red sulphuretted oxide of antimony. It is prepared 
by boiling together half a pound of the sulphuret of 
antimony in powder, and two pounds of potass, in eight 
pints of pure water, for fifteen minutes; stirring the mix- 
ture with an iron spatula ; and then expeditiously filter- 
ing it whilst it is hot. The liquor is now suflTered to stand 
in a cool place, where it soon deposits a powder that 
must be repeatedly washed, first with cold, and after- 
wards with hot w^ater, till deprived of taste. The anti- 
mony may be used again, until entirely consumed. Ac- 
cording to the quantity which is taken, Kermes' mineral 
operates as an emetic, purgati\^, sudorific, or expecto- 
rant; its active properties render half a grain in most 
cases sufficient at a time. 

Phosphorus, thrown in small pieces upon melted anti- 
mony, combines with it. The phosphuret of antimony, 
is of a white colour, brittle, and appears laminated when 
broken. 



144 CHEMISTRY. 

TELLURIUM. 

Tellurium is a recently discovered metal, nearly white 
like tin, but varying a little to the greyness of lead. Its 
fracture is laminated. It is extremely brittle, and nearly 
as fusible as lead. When heated with the blow-pipe 
upon charcoal, it burns with a very lively flame, of a 
blue colour, inclining at the edges to green. It is so 
volatile as to rise entirely into a whiti^ grej smoke, 
and exhales an odour like that of radishes. The smoke 
condenses into a white oxide. Its specific gravity is 
6.115. 

IClaproth, who discovered this metal, found it in an ore 
called the auriferous ore, otherwise aurum paradoxicuniy 
which is obtained in Transylvania, and which contains 
but a very small quantity of gold. 

Tellurium amalgamates w^ith mercury by trituration. 
It is oxidized and dissolved in the principal acids. To 
sulphuric acid it gives a deep purple colour, and if this 
acid has been diluted with two or three parts of water, 
and a little nitric acid added, a considerable portion of 
tellurium will dissolve in it, and the solution will not be 
decomposed by water. The solution in sulphuric acid 
alone is separated in black flakes, and heat throws down 
a w^hite precipitate. 

With nitric acid, tellurium forms a colourless solution, 
w^hich remains so when diluted, and affords slender, den- 
dritic crystals by evaporation. 

Tellurium dissolves in nitro-muriatic acid ; the solution 
is transparent, and the addition of water precipitates a 
white powder, which is soluble in muriatic acid. Alcohol 
produces a similar precipitate. 

Iron, tin, zinc, and antimony, precipitate tellurium 
from its acid solutions in a metallic state, under the form 
of small black flakes, which resume their splendour by 
friction, and which on burning charcoal rapidly melt into 
a metallic button. 

The alkalies throw down from the solutions of telluri- 
um, a white precipitate, which is soluble in all the acids, 
by an excess of the alkalies or their carbonates. 



TUNGSTEN. 145 

TUNGSTEN. 

TuNGSTEPf is externally of a brown colour, internally 
of a steel grey. Its specific gravity is 17.600, and it 
is extremely difficult of fusion. 

This metal is in Sweden obtained from an ore in which 
its oxide exists in combination with lime ; in Germany 
and England, it may be obtained from a mineral called 
wolfram, in which it exists in combination with iron. 
The oxide of tungsten has acid properties, and is there- 
fore called tungstic acid. 

D'Elhuyart found that wolfram contained y^^ of tung- 
stic acid ; the rest of it consisted of iron, manganese, and 
tin. This acid substance being mixed with charcoal 
powder, was violently heated in a crucible: after it had 
cooled, a button of metal was found of a dark brown 
colour, which crumbled to pieces between the fingers. 
On viewing it with a glass, it was found to consist of a 
congeries of metallic globules, some of which were as 
large as a pin head. These globules were the tungsten ; 
the charcoal had combined with the oxygen of the acid 
substance, and left the metal pure. When heat is ap- 
plied with access of air, tungsten is converted into a 
yellow powder, composed of 80 parts of tungsten, and 
20 of oxygen. This is the yellow oxide of tungsten, or 
tungstic acid. 

Vauquelin considers that the substance formed by 
combination of tungsten with oxygen, does not possess 
the properties generally attributed to acids ; since it is 
insoluble in water, does not change the blue vegetable 
colours, and has no apparent savour. He advises it 
therefore to be called merely an oxide of tungsten, ob- 
serving that Scheele, who regarded it as an acid, never 
obtained it but in a triple combination, which possesses 
acid properties. 

Morveau asserts that the oxide of tungsten renders 
vegetable colours so fixed as not to be acted upon by the 
oxy muriatic acid. 
13 



146 CHEMISTRY. 

Neither the sulphuric, the nitric, nor the muriatic acid 
dissolves either tungsten or its oxide. 

The alloys of tungsten, and the uses to which the 
metal itself may be applied, appear to be little known. 

Solutions of caustic potass, soda, and ammonia, dissolve 
the oxide of tungsten, even in the cold, forming tungstate 
of potass, soda, and ammonia. 

Tungsten refuses to unite w^ith sulphur. 

A tungstate of magnesia is formed, by mixing oxide of 
tungsten with carbonate of magnesia and water, boiling 
the mixture, and straining it. An acid will precipitate 
a white powder ; and, by evaporation, a white salt is 
obtained, which crystallizes in Httle bright spangles, 
and is unchangeable in air. 

RHODIUM. 

Rhodium is one of the new metals obtained from the 
grains of crude platina. Its specific gravity is about 11. 
It is not malleable, and has never been perfectly fused 
alone. Sulphur and arsenic render it fusible, and may 
afterwards be expelled by heat. 

Rhodium unites readily wdth every metal which Dr. 
Wollaston, its discoverer, tried, except mercury. With 
gold or silver, the alloy is malleable, not oxidized by a 
high degree of heat, but becoming encrusted with a 
black oxide when slowly cooled. One-sixth of it does 
not perceptibly alter the colour of gold, but renders it 
much less fusible. Neither the nitric, nor the nitro-mu- 
riatic acid acts on it in the state of alloy with gold or 
silver, but, if it be fused with three parts of bismuth, 
lead, or copper, the alloy is entirely soluble in a mixture 
of nitric, mixed with two parts of muriatic acid. 

URANIUM. 

Uranium is of a dark grey colour on the surface; 
within, it is a pale brown. Its hardness is about 6. It 
is more difncult of fusion than manganese. It is little 



COBALT. 147 

known, and appears not to be obtained in a state of 
purity, as the specimens of ditTerent chemists have 
varied in specific gravity from 6.440 to 9.000. 

Klaproth discovered uranium in a mineral called 
peach'bleiidy which is obtained in Saxony, and which had 
been usually considered as an ore of zinc or iron, or even 
tungsten ; but Klaproth's analysis evinced that it was the 
sulphuret of uranium. 

When exposed for some time to a red heat, in a close 
vessel, uranium suffers no change ; but by means of 
nitric acid, it is converted into a yellow oxide. This 
oxide is soluble in diluted sulphuric acid gently heated, 
and aflbrds prismatic crystals of a lemon colour. It is 
also soluble in nitromuriatic acid, and may be precipi- 
tated by alkalies. 

COBALT. 

Cobalt is of a whitish colour, inclining to a bluish or 
steel grey. When pure, it is somewhat malleable while 
red hot, and is also attracted by the magnet. Its hard- 
ness is 8, and its specific gravity is usually about 7.811. 
It is brittle, and has a dull, close-grained fracture. It is 
not acted upon by water, but tarnishes in the air; it 
requires, for its fusion, a heat not inferior to that for cast- 
iron. It has never been volatilized. 

Cobalt has been found native; but mostly in the state 
of an oxide, united with arsenic, sulphur, iron, &c. It 
is plentiful in the mines of Saxony; and is also abun- 
dantly obtained in the Mendip Hills, Somersetshire, Eng- 
land, and in a mine near Penzance, in Cornwall. 

Arsenical cobalt is of a greyish colour, and becomes 
black by exposure to air. The sulphurous ore of cobalt 
resembles the grey silver ore in its texture. 

When the oxide of cobalt has been freed from arsenic 
and sulphur, which is done by pulverizing it, washing it, 
and then exposing it to a strong heat, it has an obscure 
grey colour, and is called zaffre. When zaffre is fused 
with three parts of pulverized flints, and one of potass, 
a beautiful blue glass is obtained. This glass, when 



148 CHEMISTRY. 

pulverized and washed, constitutes the smalt of connj- 
merce. Smalt is used to give the blue colour to writing 
paper, to starch, and linen. It also supplies a blue colour 
to the painters of earthenware and porcelain, and to 
enamellers. 

Metallic cobalt may be obtained by fusing zaffre in a 
white heat, with three times its weight of black flux : 
the cobalt, when reduced, sinks to the bottom of the cru- 
cible. Or it may be obtained by fusing smalt with six or 
eight times its weight of soda. 

Cobalt resists cupellation, nor will it amalgamate with 
mercury. It forms alloys with few of the metals : that 
with tin is of a light violet colour. The metals with 
which it combines most readily are arsenic and iron : 
these, when combined with it, are separated with diffi- 
culty. With iron, the alloy is hard, and not easily 
broken : with arsenic, it is brittle, fusible, and more easily 
oxidized than pure cobalt. 

To dissolve cobalt in sulphuric acid, the acid must be 
concentrated, and distilled upon it almost to dryness. 
By washing the residuum, a portion of it dissolves in the 
water: this portion is sulphate of cobalt. The other 
part consists of oxide of cobalt. The cobalt may be 
precipitated from the water by lime and alkalies. 

Nitric acid dissolves cobalt by the assistance of a gen- 
tle heat. Lime and alkalies precipitate it from its solu- 
tion ; and an excess of alkali dissolves the precipitate. 

Muriatic acid does not dissolve cobalt without the 
assistance of heat. The nitro-muriatic acid dissolves 
cobalt more readily. This solution, much diluted, forms 
the much-admired sympathetic ink, which, when written 
with upon paper, is invisible ; but, when the paper is 
warmed, the characters appear of a beautiful green, 
that gradually disappears as the paper cools ; and the 
experiment may be repeated with the same result for an 
indefinite number of times. 

Sulphur is not readily combined with cobalt by art ; 
but alkaline sulphurets readily form the combination. 

The phosphuret of cobalt may be formed by dropping 



MOLYBDENUM. 149 

small pieces of phosphorus upon ignited cobalt in grains. 
It is white and brittle, and soon loses its lustre by expo- 
sure to the air : it is more fusible than cobalt. 

MOLYBDENUM. 

The ore containing molybdenum has almost the ap- 
pearance of plumbago, and therefore, though scaly and 
more shining, it was, before it was carefully analyzed, 
mistaken for that mineral. It is unctuous to the touch, 
soils the fingers, and makes whitish and brilliant traces 
upon paper, whereas the traces of plumbago are dull. 
It has never been perfectly reduced ; when made into a 
paste with linseed oil, or any other suitable substance, 
the strongest fires only agglutinate it in brittle masses, 
consisting of small grains. These grains are of a wliitish 
yellow colour, but their fracture is a whitish grey.^^, Their 
specific gravity is at least 7.500, 

The alloys of molybdenum have been little examined ; 
those with silver, iron, and copper, are friable; those 
with lead and tin pulverulent and fusible. 

Molybdenum, by a strong heat, is gradually converted 
into a whitish coloured oxide. Nitric acid, which has a 
rapid action upon it, converts it into a white oxide. This 
oxide has the properties of an acid, and is therefore called 
molybdic acid. It dissolves in 576 parts of water at a 
mean temperature. It decomposes the, solutions of soap, 
and precipitates alkaline sulphurets. 

The muriatic acid has no action upon molybdenum, 
but dissolves its acid, which is also done by the sulphuric. 
Heat should be employed with both these acids, 

Scheele discovered, 1, that fixed alkali rendered 
molybdic acid more soluble in water ; 2, that salt pre- 
vents the acid of molybdenum from volatilization by 
heat ; 3, th<it moiybdate of potass falls down by cooling, 
in small crystalline grains, and that it may likewise be 
separated from its solvent by sulphuric and muriatic 
acids. 

Blue carmine is prepared by precipitating tin froip its 
13* 



150 CHEMISTRY. 

solution in muriatic acid with the molybdate of potass. 
The muriatic acid unites with the alkah, and the molyb- 
dic with the tin, to form the blue precipitate. 

MANGANESE. 

A MINERAL, called the soap of glass, has been employed 
for time immemorial in the manufacture of glass, which 
it whitens and renders colourless. It is usually of a grey 
or blackish colour, and soils the fingers. This mineral is 
the oxide of a peculiar metal called maagancs'\ 

Metallic manganese is of a greyish while colour, brit- 
tle, though not easily broken, and devoid of malleability. 
When reduced to powder, it is attracted by the magnet. 
Its specific gravity is 6.990 ; its hardness is 8. It is more 
difficult of fusion than iron. 

When manganese is exposed to the atmosphere, it soon 
tarnishes, and becomes at last black and friable; heat 
accelerates this change ; which produces the substance 
called black oxide of manganese. It is this oxide of the 
metal which is usually employed in the arts, and in which 
state manganese i^; generally found. The counties of 
Somerset and Devon supply large quantities of it, and in 
the vicinity of Aberdeen, a mine of it has been lately 
discovered, which furnishes twenty tons per week. 

The black oxide of manganese contains 25 per cent, 
of oxygen ; a portion of this oxygen is separated by heat, 
and, therefore, the oxide has recently become important, 
for the purpose of furnishing this gas. When manganese 
is employed in preparing oxymuriatic acid for medicine, 
the purest, such as that from Upton Pyne, should be 
used. That from Bristol and the Mendip Hills, generally 
contains lead. 

Manganese is susceptible of three different degrees of 
oxydizement, forming the vyhite, the red, and the black 
oxides of manganese. An oxide containing still more 
oxygen is asserted to be of a dark green. 

Metallic manganese may be obtained, by mixing the 
black oxide into a ball with linseed oil ; putting this ball 



TANTALIUM. 151 

into a cavity made in a lump of charcoal, covering it 
with a layer of charcoal, enclosing the whole in a cruci- 
ble, and subjecting it to an intense heat for one or two 
hours. Saline fluxes should be rejected for reducing 
this mineral, because it has so strong a disposition to 
vitrify, that it would be suspended in a llux of that kind. 

Manganese unites by fusion with all the metals except 
mercury. With copper and iron it appears to combine 
the most readily ; but none of its alloys are used in the 
arts, or known to be valuable. 

The sulphuric acid attacks manganese, and produces 
hydrogen gas ; the solution goes on more slowly than 
that of iron in the same acid ; it is colourless. Sulphuric 
acid extricates from the oxide of manganese, a large 
quantity of oxygen gas. 

The oxide of manganese is dissolved by nitric acid ; 
muriatic acid, digested upon it, seizes its oxygen, and 
passes in vapour through the water. This vapour is 
oxymuriatic acid. 

The oxide of manganese combines with the alkalies. 
It also combines with sulphur, which the metal does 
not. 

Manganese at a red heat combines with phosphorus. 
The phosphuret is of a white colour, brittle, granulated, 
disposed to crystallize, not altered by exposure to the air, 
and more fusible than manganese. 

TANTALIUM. 

From a fossil called tantalite, and another called ytro- 
tantalite, Ekeberg extracted by means of the fixed 
alkalies, a white powder, which he ascertained to be the 
oxide of a peculiar metal. To this metal he gave the 
name of tantalium. 

When the oxide of tantalium above mentioned is 
powerfully heated wdth charcoal, a button of metal is 
obtained, with a metallic lustre externally, but internally 
black and without brilliancy. Its hardness is 7 ; its 
specific gravity, 6.5. The acids will reduce it again to 



152 CHEMISTRY. 

the state of white oxide, but they will not dissolve it. 
The oxide is not changed by a red heat. Caustic fixed 
alkali is the only re-agent which has any action upon it. 

TITANIUM. 

Titanium is of a brownish red colour, almost like cop- 
per. Its lustre is considerable, it is brittle, and very 
difficult of fusion. Its specific gravity is 4.18; its hard- 
ness 9. 

Titanium is obtained from a mineral, plentiful in Hun- 
gary, called red schorl , which is its native red oxide ; 
and from another mineral obtained in Cornwall, called 
manacanite. 

Vanquelin obtained metallic titanium from its native 
red oxide, by mixing together 100 parts of this oxide 
with 50 of calcined borax, and 50 of charcoal, formed 
into a paste with oil ; and exposed the whole to the heat 
of a forge raised to 166° of Wedgwood. 

This metal is acted upon by the principal acids, except 
the nitric, and forms salts w^ith them. It also combines 
with phosphorus. The phosphuret is of a pale white 
colour, brittle, granular, and infusible by the blow-pipe. 

The attempts to alloy titanium have not succeeded. 

CHROMIUM. 

Chromium is of a whitish colour, inclining to grey ; it 
is very brittle; its fracture presents a radiated appear- 
ance, needles crossing in different directions, with inter- 
stices between them. It is difficult of fusion, resisting the 
heat of the blow-pipe. 

Chromium was discovered by Vanquelin, in analyzing 
a beautiful mineral called red lead of Siberia. The 
mineral is a chromate of lead, in which chromium exists 
in the state of an acid. Its colour is a fine aurora red, 
with considerable lustre. Chromium has also been found 
united w^ith iron, forming chromate of iron ; it algo exists 
in some gems, of which it lappears to constitute the col- 



CHROMIUM. 153 

curing principle. In the emerald it exists in a state of 
green oxide, and the spiral ruby contains it in the state 
of an acid. 

Vanquelin extracted this metal from the red-lead ore, 
by adding to it muriatic acid, which combines with the 
oxide of lead, and forms a compound that is precipitated, 
the chromic acid remaining in solution. To abstract a 
little muriatic acid combined with it, oxide of silver is 
cautiously added, and the pure chromic acid, being de- 
canted from the precipitate of muriate of silver, and 
evaporated, is exposed to a very strong heat, excited 
by a forge, in a crucible of charcoal, placed within 
another of porcelain. It is thus reduced to the metallic 
state. 

Sulphuric acid decomposes the red-lead ore ; but it is 
difficult to separate the products. Nitric acid does not 
decompose this ore. 

Chromic acid is very soluble in water: it is of an 
orange-red colour, with a pungent metallic taste. By 
evaporation, it aflbrds crystals, in long slender prisms, of 
a ruby-red colour. This acid combines with the alka- 
lies, earths, and metallic oxides, and the neutral salts 
which it forms with them are called chromates. 

The combinations of this acid with metallic oxides are 
in general possessed of very beautiful colours, and are 
well adapted to the purposes of painting. That with 
oxide of lead is an orange-yellow, of various shades ; 
that with mercury, a vermilion-red ; with silver, a car- 
mine-red ; with zinc and bismuth, the colours are yel- 
low ; with copper, cobalt, and antimony, they are dull. 

The term chromium is derived from a Greek word 
signifying colour, and is applied to this metal on account 
of the diversity of colours which its compounds form. 

The specific gravity of chromium, and the four follow- 
ing metals, is uncertain. 



154 CHEMISTRY. 

COLUMBIUM. 

A MINERAL in the British Museum, sent to Sir Hans 
Sloane, with some iron, from Massachusetts, upon being 
examined by Hatchett, was found to contain a new me- 
tallic substance, to which that eminent chemist has giver^ 
the name of columbium. 

The ore of columbium has never been perfectly re- 
duced, but it affords an acid, called the columbic acid, 
which differs from all other bodies. The alkalies throw 
it down from its acid solutions, in white flakes. Prussiate 
of potass changes the blue colour to an olive green, and 
a precipitate of the same colour is gradually formed. 
Tincture of galls produces a deep orange coloured precip- 
itate. Zinc occasions a white precipitate. The fixed 
alkalies readily combine with the columbic acid. It is 
insoluble and unalterable with regard to colour by the 
nitric acid. 

CERIUM. 

Cerium is another newly discovered metal, which 
exists in a mineral called cetite. Cerite is semi-transpa- 
rent, generally of a reddish colour, though occasionally • 
yellowish. Some specimens are hard enough to scratch 
glass, and to strike fire with steel. To obtain the oxide 
of cerium, this mineral is pulverized, calcined, and dissol- 
ved in nitro-muriatic acid. The filtered solution, being 
neutralized with potass, is to be precipitated by nitrate 
of potass, and the precipitate, well washed, and after- 
wards calcined, is oxide of cerium. This oxide is 
susceptible of two degrees of oxidation ; in the first it is 
white, and this by calcination becomes of a fallow red. 

The white pxide of cerium, mixed with a large pro- 
portion of borax, fuses into a transparent globule; but 
in attempts to obtain the metallic cerium, the quantity 
operated upon has always been so far dissipated, that 
the sensible properties of the metal are unknown. 



OSMIU3I. 155 

IRIDIUM. 

In a black powder, left after dissolving crude platina, 
Tennant discovered two new metals, to one of which, he 
gave the name of iridium. To analyze this powder, it 
was mixed with pure dry soda, and kept at a red heat 
for some time, in a silver crucible. The alkali was then 
separated by solution in water, and the undissolved part 
of the powder was digested with muriatic acid, with 
which a solution, at first of a dark blue, was obtained ; 
it afterwards became of a dusky olive-green, and at last, 
of a deep red. This acid solution contains two metals, 
but chiefly iridium. By its evaporation, may be obtained 
an imperfectly-crystallized mass, which, dissolved in wa- 
ter, gives, by evaporation, distinct octahedral crystals. 
These crystals, dissolved in water, produce a deep red 
solution, inclining to orange. By exposure to heat, the 
acid may be expelled ; but the iridium thus produced 
has never been fused, except by a powerful galvanic 
battery. Its oxide, when obtained as above stated, is 
white: it neither combines with sulphur nor arsenic. 
Lead unites with it easily, but is separated by cupel la- 
tion, leaving the iridium on the cupel, in" the form of a 
coarse black powder. Copper and silver form with it 
malleable alloys; but the iridium appears to be diffused 
through the silver only in the state of a fine powder. 
Gold remains malleable, although alloyed with a con- 
siderable portion of it; and is not separated from it 
either by cupellation or quartation. 

OSMIUM. 

The metal found along with iridium, in the black 
pow^der left after dissolving platina, is called osmium. 

The oxide of osmium may be obtained by distilling 
with nitre the black powder above-mentioned : at a low 
red heat, an apparently oily fluid sublimes into the neck 
of the retort, which, on cooling, concretes into a solid, 
colourless, semi-transparent mass. This, being dissolved 



156 CHEMISTRY. 

in water, forms a concentrated solution of oxide of os- 
nnium. This solution indelibly stains the skin of a deep 
red or black. Infusion of galls renders the solution at 
first purple, but in a little time, it becomes of a deep 
vivid blue. If mercury be agitated with the solution, it 
forms with the osmium a perfect amalgam. Part of the 
mercury may be separated by squeezing it through 
leather, and the rest by distillation, which will leave the 
osmium pure, in the state of a black powder. This 
powder has never been fused. It forms malleable al- 
loys with copper and gold. 

OF ACIDS. 

Acids possess most or all of the following properties : 

1. They excite the sensation called sourness or acidity. 

2. They change the blue, green, and purple juices of 
vegetables to red. 3. They combine with alkalies, earths, 
and metallic oxides ; with which they form compounds, 
called salts, 4. They combine with water in all pro- 
portions. 

Most of the acids have been proved to contain oxygen 
as a component part ; and are more or less strong in pro- 
portion as they are combined with more or less oxygen. 
They are not all, however, capable of combining with 
more than one dose or proportion of oxygen : a few are 
capable of combining with two doses of oxygen, and a 
still smaller number with three. No acid has been ob- 
tained by itself in combination with a fourth proportion 
of oxygen. These differences it becomes necessary to 
distinguish ; and the distinction is made in the following 
manner. 

When any body contains the smallest portion of oxy- 
gen, which converts it into an acid, the name of the base 
or radical of the acid is terminated by ous ; thus, we 
have the sulphurous acid. The next degree of oxygen- 
isement is expressed by the termination ic ; thus, we 
say, sulphuric acid. The third degree is expressed by 
the addition of the word oxygenized, or its contraction, 



ACETIC ACID. 157 

oxy ; thus, we have the oxymuriatic acid. A fourth de- 
gree of oxygenizement may be expressed by placing the 
term hyper before that of oxy ; thus, we have hyper- 
oxymuriatic acid. There is only one instance of this 
last mode of expression being necessary, and that instance 
only refers to the acid as it is supposed to exist in com- 
bination with another body. 

ACERIC ACID. 

A PECULIAR acid, said to exist in the juice of the ma- 
ple. It is decomposed by heat, like the other vegetable 
acids. 

ACETIC ACID. 

Acetic acid may be obtained from crystallized acetate 
of copper, which must be reduced to powder, and dis- 
tilled. A fluid, possessing little acidity, first rises, and 
afterwards, a powerful acid. This acid has a greenish 
hue when first prepared, because a small part of the 
oxide of copper comes over with it ; but it may be ob- 
tained, perfectly colourless, by distilling it with a gentle 
heat. It may also be prepared, with more certainty as 
to its freedom from copper, by distilling acetate of soda, 
or acetate of potass, with half its weight of sulphuric 
acid. 

Acetic acid is sold under the name of radical vinegar. 
It is colourless like water : its smell is extremely pun- 
gent, and its taste acrid. When applied to the skin, it 
reddens and corrodes it. It is extremely volatile, wholly 
evaporating on exposure to the air: and, when heated 
in the open air, it takes fire readily. At 50°, it freezes. 
It unites with water in any proportion ; and on mixture 
with it, heat is evolved. It dissolves camphor; and, 
wdth the addition of essential oils, forms the aromatic 
vinegar. 

Acetic acid is used for smelling at ; crystals of sulphate 
of potass being put into a bottle, and moistened with it 
for that purpose. This mixture is called volatile salt of 
14 



158 CHEMISTRY. 

vinegar. A few drops of sulphuric acid, added to a 
phial of the acetate of potass, make a strong smelling- 
bottle by the evolutions of the acetic acid. 

Acetic acid may be advantageously employed to sepa- 
rate manganese from iron. When both metals are dis- 
solved in this acid, and the solution is evaporated to dry- 
ness, the acid adheres to the manganese, but abandons 
the iron. Water will then dissolve the acetate of man- 
ganese from the oxide of iron. Two or three evapora- 
tions and solutions are suffioient to remove the whole of 
its iron. 

Acetic acid consists of oxygen, hydrogen, and carbon, 
but the proportions of its component parts have not been 
clearly proved ; with various bases, it forms the salts 
called acetates. 

BENZOIC ACID. 

This acid is obtained from the resin called benzoin or 
benjamin, which is brought from the East Indies. By a 
gentle heat the resin is sublimed, and condenses in the 
form of long needles, or straight filaments of a white 
colour, crossing each other in all directions. These are 
what are sold under the name oi jioioers of benjamin, 
and consist of the acid in question. When pure, they 
are of a brilliant white, have an aromatic odour, are 
entirely soluble in alcohol, but the addition of water 
causes a precipitate. Hot water dissolves them copi- 
ously, but cold water scarcely at all. They are not 
altered by the air ; their taste is acrid and bitter. They 
form a kind of paste if rubbed in a mortar. 

The purest benzoic acid may be obtained in the 
humid way, by boiling the resin with carbonate of soda, 
and adding diluted sulphuric acid to the filtered decoc- 
tion as long as it produces any precipitation. The pre- 
cipitate is the benzoic acid. 

Benzoic acid is so inflammable, that it burns with a 
clear yellow flame, without the assistance of a wick. 
The mineral acids dissolve it, but it separates from them 
without alteration, by the addition of water. It dissolves 



ARSENIOUS ACID. 159 

in oils, and melted tallow. It unites with earthy and 
alkaline bases, forming the salts called benzoates. 

AMNIOTIC ACID. 

A PECULIAR acid found in the liquor of the amnois of 
the cow. It exists in the form of a white pulverulent 
powder. It is slightly acid to the taste, but sensibly 
reddens vegetable blues. It is with difficulty soluble in 
cold, but readily soluble in boiling water, and in alcohol. 
When exposed to a strong heat, it exhales an odour of 
ammonia and of prussic acid. Assisted by heat, it decom- 
poses carbonate of potassa, soda, and ammonia. It pro- 
duces no change in the solutions of silver, lead, or mer- 
cury, in nitric acid. Amniotic acid may be obtained by 
evaporating the liquor of the amnois of the cow to a 
fourth part, and suffering it to cool ; crystals of amniotic 
acid will be obtained in considerable quantity. Whether 
this acid exists in the liquor of the amnois of other ani- 
mals, is not yet known. 

ARSENIOUS ACID. 

This is nothing more than the white oxide of arsenic 
sold from the stores, without any preparation. It has a 
weakly acid taste, and sensibly reddens the tincture of 
cabbage and litmus, and most other vegetable blues ; the 
syrup of violets, which it turns green, is an exception. 
If thrown on burning coals, or a red-hot iron, it is vola- 
tilized in the form of a white vapour, which emits the 
smell of garlic. By a strong heat it is vitrified into a 
transparent glass. It only contains about seven per cent, 
of oxygen. 

Arsenious acid is soluble in 15 times its weight of boil- 
ing water, but requires for its solution eighty times its 
weight of cold water. The solution crystallizes best by 
slow evaporation ; it is very acrid ; it unites with the 
earthy bases, decomposes the alkaline sulphurets, and 
forms with them a yellow precipitate, in which the 
arsenic approaches to the metallic state. 



160 CHEMISTRY. 

The combinations of arsenious acid with different bases 
are called arsenites, 

BORACIC ACID. 

BoRAcic acid is procured from the salt called borax, in 
the following manner: the borax is dissolved in hot 
water, and the solution filtered ; sulphuric acid is added 
very gradually to the solution, till it has a sensibly acid 
taste ; being then left to cool, a number of small, shining, 
laminated crystals form in it ; these crystals are the 
boracic acid ; they are to be washed with cold water, 
and dried upon brown paper. 

The crystals of boracic acid are thin irregular hexa- 
gons, of a silvery whiteness. They are soft and unctuous 
to the touch, almost like spermaceti. They have no 
smell, but a bitterish taste, with a slight degree of acidity ; 
and they are unalterable in the air. When mixed with 
spirit of wine, they cause it to burn with a green flame. 
When sulphuric acid is poured upon them, a transient 
odour of musk is perceived. 

Boracic acid, when exposed to a violent fire, is converted 
into a transparent glass ; this glass is soluble in water, 
and the acid is again produced from evaporation. 

It is much employed in analyzing minerals, as it brings 
almost all the stones into solution. 

BUTYRIC ACID. 

We owe the discovery of this acid to M. Chevreul. 
Butter, he says, is composed of two fat bodies, analogous 
to those of hogs' lard, of a colouring principle, and a 
remarkably odorous one, to which it owes the properties 
that distinguish it from the fats, properly so called. This 
principle, which he has called butyric acid, forms well 
characterized salts with barytes, strontian, lime, the 
oxides of copper, lead, &c. ; 100 parts of it neutralize 
a quantity of base which contains 10 of oxygen. M. 
Chevreul has not explained his method of separating 
this acid from the other constituents of butter. 



CAMPHORIC ACID, CARBONIC ACID. 161 

CAMPHORIC ACID. 

Camphor is a concrete essential oil, of a strong taste 
and smell ; it is extracted by sublimation from a species 
of laurel in the East Indies, and has a crystalline form. 
It is so volatile, that it cannot be melted in open vessels, 
and so imflammable, that it burns even on the surface of 
water. Kosegarten, by distilling nitric acid eight times 
successively from this substance, obtained an acid in 
crystals, which is called camphoric acid. 

Camphoric acid is in snow-white crystals, which efflo- 
resce in the air. It has a slightly acid, bitter taste, and 
a smell like saffron. It reddens vegetable blues. It re- 
quires 200 times its w^eight of cold water to dissolve it ; 
but boiling water takes up one-twelfth. If thrown upon 
burning coals, it is entirely dissipated in a thick aromatic 
smoke. With a gentle heat it melts and is sublimed. 
It is soluble in alcohol, and not precipitated from it by 
the addition of water, a property which distinguishes it 
li'om the benzoic acid. It does not precipitate lime from 
lime-water. 

The mineral acids dissolve camphoric acid entirely, it 
is also dissolved by the fixed and volatile oils. It unites 
readily with the earths and alkalies, forming the salts 
called camphorates. 

CARBONIC ACID. 

Carbonic acid gas is the result of the combustion of 
carbon. Every 100 parts of it, according to Tennant, 
contain 18 parts of carbon and 82 of oxygen. Its 
weight is to atmospheric air as 1500 to 1000. It has no 
smell ; is invisible and elastic, hke common air, but 
extinguishes flame, and is totally unfit for respiration. 

Carbonic acid is contained in the air to the amount of 
about one part in the thousand. It is absorbed by water 
if agitated, or long in contact with it. Strong pressure 
will cause the w^ater to absorb three times its bulk of 
this gas, which imparts to it a taste agreeably acidulous, 
14% 



162 CHEMISTRY. 

and causes it to have a sparkling lustre when poured 
from one vessel to another. The Pyrmont, Spa, and 
Seltzer waters, are neutral combinations of carbonic 
acid with water, and they can be imitated by art with 
the greatest precision. 

The specific gravity of water saturated with carbonic 
acid is 1.0015. If water containing carbonic acid be 
frozen, the whole of this gas separates in freezing, and, 
therefore, ice is never found to contain any. A boiling 
heat also produces this separation. 

Carbonic acid, from its gravity, may be poured from 
one vessel to another, but if a portion of it be left in an 
open vessel, for any length of time, it will be found to 
have escaped ; the air having an attraction for it, gradu- 
ally absorbs it, and will even abstract it from water. 

Carbonic acid exists in incalculable quantities, com- 
bined with other substances. Marble, limestone, and 
chalk consist of it in combination with lime: it forms 
about one-third of their weight, and may be disengaged 
from any of these substances, by means of an acid, or 
considerable heat. The former means is generally more 
convenient, when a quantity is required for the purpose 
of experiment. The sulphuric acid, diluted with about 
six times its weight of water, is poured upon the marble, 
chalk, or limestone, previously reduced to a powder. An 
effervescence immediately ensues : this is occasioned by 
the extrication of carbonic acid gas, which must be col- 
lected by meafiS of the pneumatic apparatus. The mer- 
curial trough should be used, if the gas is not intended 
for immediate use. 

Alcohol, and spirit of turpentine, absorb double their 
weight of carbonic acid gas; olive oil, its own bulk. 
Ether mixes with it in the state of gas. 

Carbonic acid enters into combination with alkalies, 
alkaline earths, alumine, zircon, and metallic oxides, 
with which it forms salts called carbonates. 

Water, impregnated with carbonic acid, and applied 
to the roots of plants, is highly favourable to vegetation ; 
but, if this gas be applied to the leaves, as an atmo- 
sphere, it is injurious. 



CASEIC ACID, CHLORIC ACID. 163 

CASEIC ACID. 

The name given by Proust to an acid formed in 
cheeses, to which he ascribes their flavour. 

CHLORIC ACID. 

This acid was first eliminated from salts contain- 
ing it by Gay Lussac, and described by him, in his ad- 
mirable memoir on iodine. When a current of chlorine 
is passed for some time through a solution of barytic 
earth, in warm water, a substance called hyper-oxy- 
muriate of barytes, by its first discoverer, Chenevix, is 
formed, as well as some common muriate. The latter 
is separated, by boiling phosphate of silver in the com- 
pound solution. The former may then be obtained by 
evaporation, in fine rhomboidal prisms. Into a diluted 
solution of this salt, Gay Lussac poured weak sulphuric 
acid. Though he added only a few drops of acid, not 
nearly enough to saturate the barytes, the liquid became 
sensibly acid, and not a bubble of oxygen escaped. By 
continuing to add sulphuric acid with caution, he suc- 
ceeded in obtaining an acid liquid, entirely free from 
sulphuric acid and barytes, and not precipitating nitrate 
of silver. It was chloric acid dissolved in water. 

This acid has no sensible smell. Its solution in water 
is perfectly colourless. Its taste is very acid, and it red- 
dens litmus without destroying the colour. It produces 
no alteration on solution of indigo in sulphuric acid. Light 
does not decompose it. It may be concentrated by a 
gentle heat, without undergoing decomposition, or with- 
out evaporating. It was kept a long time exposed to the 
air without sensible diminution of its quantity. When 
concentrated it has something of an oily consistency. 
When exposed to heat, it is partly decomposed into 
oxygen and chlorine, and partly volatilized without 
alteration. Muriatic acid decomposes it in the same 
way, at the common temperature. Sulphurous acid, and 
sulphuretted hydrogen, have the same property; but 



164 CHEMISTRY. 

nitric acid produces no change upon it. Combined with 
ammonia, it forms a fulminating salt. It does not pre- 
cipitate any metallic solution. It readily dissolves zinc, 
disengaging hydrogen ; but it acts slowly on mercury. It 
cannot be obtained in the gaseous state. Its taste is not 
only acid but astringent, and its colour, when concentra- 
ted, is somew^hat pungent. 

Chloric acid combines with the bases, and forms the 
chlorates, a set of salts formerly known by the name of 
hyper-oxygenated muriates, 

CHLORIODIC ACID, 

Sir H. Davy formed it, by admitting chlorine in excess 
to known quantities of iodine, in vessels exhausted of air, 
and repeatedly heating the sublimate. Operating in this 
way, he found that iodine absorbs less than one-third of 
its weight of chlorine. 

Chloriodic acid, a very volatile substance, formed by 
the sublimation of iodine in a great excess of chlorine, 
is of a bright yellow colour ; when fused it becomes of a 
deep orange, and when rendered elastic, it forms a deep 
orange coloured gas. It is capable of combining with 
much iodine when they are heated together ; its colour 
becomes, in consequence, deeper, and the chloriodic acid 
and the iodine rise together in the elastic state. The 
solution of the chloriodic acid in water, likewise dissolves 
large quantities of iodine, so that it is possible to obtain 
a fluid containing very different proportions of iodine and 
chlorine. 

When two bodies so similar in their characters, and in 
the compounds they form, as iodine and chlorine, act 
upon substances at the same time, it is difficult. Sir H, 
Davy observes, to form a judgment of the different parts 
they play in the new chemical arrangement produced. 
It appears most probable, that the acid property of the 
chloriodic compound depends upon the combination of the 
two bodies ; and its action upon solutions of the alkalies 
and the earths may be easily explained, when it is con- 



CHROMIC ACID, CITRIC ACID, 165 

sidered that chlorine has a greater tendency than iodine 
to form double compounds with the metals, that iodine 
has a greater tendency than chlorine to form triple 
compounds with oxygen and the metals. 

A triple compound of this kind with sodium may exist 
in sea-water, and would be separated with the first crys- 
tals that are formed by its evaporation. Hence, it may 
exist in common salt. Sir H. Davy ascertained by feeding 
birds with bread soaked with water, holding some of it 
in solution, that it is not poisonous like iodine itself. 

CHROMIC ACID. 

This acid is furnished by the mineral called the red 
lead ore of Siberia, which is a chromate of lead, and 
from which chromium is obtained. It also exists in the 
chromate of iron, which is more common than the former 
mineral, and in France is even abundant. 

The acid is extracted from the real lead ore of Siberia, 
by boiling 100 parts of this mineral, with 300 of carbo- 
nate of potass, and 400 of water, and separating the 
alkali by means of weak nitric acid. It is an orange 
coloured powder, which has an acrid, metallic taste, is 
soluble in water, and crystallizable. If exposed to the 
action of light and heat, this powder loses oxygen and 
its acid properties, and is converted into the green oxide 
of chromium. 

If the muriatic acid be distilled upon the chromic acid, 
it is oxygenized, and if simply mixed with the chromic 
acid, the same effect takes place, for it acquires the 
property of dissolving gold. This arises from the readi- 
ness with which chromic acid parts with its oxygen. 

Chromic acid unites readily with alkalies. It also 
unites with borax, glass, and phosphoric acid, to which 
it communicates an emerald green colour. 

CITRIC ACID. 

The citric acid is found in the juice of lemons, oranges, 
unripe grapes, and some other fruits. It is extremely 



166 CHEMISTRY. 

acid to the taste, crystallizable, and very soluble in 
water : cold water dissolves rather more than its own 
weight of it, and hot water double its w^eight The 
solution undergoes a spontaneous decomposition by long 
keeping. 

If lemon juice be exposed in an open vessel, it deposits 
a quantity of mucilage, from which it may be separated 
by decantation and Alteration. If the juice thus purified, 
be exposed to a freezing temperature, and the ice formed 
in it, which consists only of its aqueous particles, be re- 
moved as it is formed, the lemon juice will be obtained 
in a state of high concentration. Its quantity will be 
only about one-eighth of what it was at first, but its 
strength will be eight times greater. It may be kept for 
use, or may be made into dry lemonade, by adding six 
times its weight of fine loaf-sugar in powder. 

The lemon juice, prepared as above, is not pure citric 
acid, but it retains a flavour which renders it better for 
domestic use than if it w^ere pure. To prepare pure 
citric acid, Scheele saturated lemon-juice with lime, 
edulcorated the precipitate, which consisted of citric 
acid and lime, separated the lime from it by diluted 
sulphuric acid, cleared it from the sulphate of lime by 
repeated filterations and evaporations ; then evaporated 
it to the consistence of a syrup, and set it in a cool place : 
a quantity of crystals formed which were pure citric acid. 
Like the oxalic acid, it possesses the property of speedily 
dissolving the oxides of iron. The dyers make use of it, 
for no other acid can be employed with so much success 
in enlivening the colours given by saifron : it appears 
also that it will form with granitin, a liquor which with 
cochineal, produces a scarlet colour superior to the usual 
dye, especially with silk and morocco leather. Citric 
acid whitens and hardens tallow, but as tartaric acid acts 
nearly as well in this respect, and is considerably cheap- 
er, it is seldom made use of for this purpose. 

Citric acid oxidizes iron, zinc, and tin. It does not act 
upon gold, silver, platina, mercury, bismuth, antimony, 
or arsenic. 



COLUMBIC ACID, DELPHINIC ACID. 167 

The combinations of the citric acid with the different 
bases, are called citrates. 

COLUMBIC ACID. 

The experiments of Hatchett have proved that a pe- 
culiar mineral, found in Massachusetts, deposited in the 
British Museum, consisted of one part of oxide of iron, 
and somewhat more than three of a white coloured sub- 
stance, possessing the properties of an acid. Its basis 
was metallic. Hence, he named this columbium, and 
the acid, the columbic. Dr. Wollaston, by very exact 
analytical comparisons, proved that the acid of Hatchett 
was the oxide of the metal lately discovered in Sweden 
by Ekeberg, in the mineral ytrotantalite, and thence 
called tantalum. Dr. Wollaston's method of separating 
the acid from the mineral is peculiarly elegant. One 
part 6f tantalite, five parts of carbonate of potassa, and 
two parts of borax, are fused together in a platina cru- 
cible. The mass, after being softened in water, is acted 
on by muriatic acid. The iron and manganese dissolve, 
while the columbic acid remains at the bottom. It is in 
the form of a white powder, which is insoluble in nitric 
and sulphuric acids, but partially in muriatic. It forms, 
with barytes, an insoluble salt, of which the proportions, 
according to Berzelius, are 24.4 acid, and 9.70 barytes. 
By oxidizing a portion of the tantalum or columbium, 
Berzelius concludes the composition of the acid to be 
100 metal, and 5.485 oxygen. 

DELPHINIC ACID. 

The name of an acid extracted from the oil of the dol- 
phin. It resembles a volatile oil ; has a light lemon 
colour, and a strong aromatic odour, analogous to that 
of rancid butter. Its taste is pungent, and its vapour has 
a sweetened taste of ether. It is slightly soluble in 
water, and very soluble in alcohol. The latter solution 
strongly reddens litmus. 100 parts of delphinic acid 



168 CHEMISTRY. 

neutralize a quantity of base which contains 9 of oxy- 
gen; whence, its prime equivalent appears to be 11.11. 

ELLAGIC ACID. 

So named by Braconnet, by reversing the word galle. 
The deposit, which forms in infusion of nut-galls left to 
itself, is not composed solely of gallic acid, and a matter 
which colours it. It contains, beside a little gallate and 
sulphate of lime, and a new acid, which was pointed out 
by Chevreuil, in 1815, an acid on which Braconnet made 
observations in 1818, and which he proposed to call acid 
ellagic, from the word galle, reversed. Probably this 
acid does not exist ready formed in nut-galls. It is in- 
soluble ; and, carrying down with it the greater part of 
the gallic acid, forms the yellowish crystalline deposit. 
But boiling water removes the gallic acid from the ella- 
gic ; whence, the means of separating them one from 
another. 

It has a pale yellow lemon colour, but no smell. Heat 
and light decompose it. Hydroeganic acid is then formed, 
and white ferro-prussiate of iron, which soon becomes 
blue. Its affinity for the bases enables it to displace acetic 
acid, without heat, from the acetates, and to form ferro- 
prussiates. 

FLUORIC ACID. 

This acid is contained in the mineral called jluor or 
fusible spar, which consists of fluoric acid and lime. If 
sulphuric acid be poured upon this spar in powder, the 
lime combines with it to form sulphate of lime, and the 
fluoric acid is expelled, and they may be collected by the 
pneumatic apparatus. The sulphuric acid should be 
well concentrated, and equal in weight to the fluor spar. 
A leaden retort must be used in the distillation, and 
only a gentle heat will be required. The gas should be 
received over mercury. 

Fluoric acid gas is invisible and elastic like common 
air ; it will not maintain combustion, and cannot be 



FLUORIC ACID. 169 

breathed without causing death. It has the odour of 
muriatic acid, but is more corrosive, and when exposed 
to a moist atmosphere, it becomes cloudy. 

Fluoric acid gas is heavier than common air. It cor- 
rodes the skin almost instantly. It combines rapidly 
with water, with which it forms liquid fluoric acid ; as it 
dissolves silex, it cannot be prepared in glass vessels, nor 
kept in them, unless they be lined internally with wax 
or some similar coating. The acid combines with the 
silex of glass, and the silex passes over with it in the 
distillation. It is for this reason that it is usually kept 
as well as prepared in leaden or tin bottles. It is absorb- 
ed by alcohol and ether without altering their qualities : 
water impregnated with it must be cooled down to 23^ 
before it will freeze. 

The action of fluoric acfd, upon all inflammable sub- 
stances, is, in general, very feeble. 

It will oxidize iron, zinc, copper, and arsenic ; but 
has no action upon platina, gold, silver, lead, tin, anti- 
mony, cobalt, mercury. 

It combines with alkalies, alkaline earths, alumine, 
arid metallic oxides; and forms the salts caiWed Jluates, 

Fluoric acid has been discovered in the enamel of 
the human teeth, and in ivory. Vanquelin also found it 
in topaz. 

The only use to which fluoric acid has been applied, 
is that of etching upon glass. For this purpose, either 
the liquid fluoric acid may be employed, or the gas. If 
the former, the glass remains polished where the acid 
has corroded ; but with the gas, the lines have the ap- 
pearance as if the glass had been ground, and not polished. 
Landscapes, and other designs, properly executed upon 
glass, by means of this acid, have an elegant appear- 
ance. The process is the same as that for etching upon 
copper, except that so much care is not necessary in pre- 
paring the ground : bees'- wax alone will sufllce. 

15 



170 CHEMISTRY. 

GALLIC ACID. 

This acid is found in the nut-galls, and generally, in 
all astringent vegetables, though it exists independently 
of the astringent principle. The nut-gall is an excres- 
cence produced on a species of oak, by the puncture of 
an insect. 

The gallic acid may be obtained by various processes : 
the following method is proposed by Proust. Pour a 
solution of the muriate of tin into an infusion of nut-galls ; 
a copious yellov^ precipitate is instantly formed, consist- 
ing of the tanning principle, combined with the oxide of 
tin. After diluting the liquor with a sufficient quantity 
of water to separate any portion of this precipitate which 
the acids might hold in solution, the precipitate is to be 
separated by Alteration. The liquid contains gallic acid, 
muriatic acid, and muriate of tin. To separate the tin, 
a quantity of the sulphuretted hydrogen gas is to be 
mixed with the liquid. Sulphuret of oxide of tin is pre- 
cipitated under the form of a brown powder. The liquid 
is then to be exposed for some days to the light, covered 
with paper, till the superfluous sulphuretted hydrogen 
gas exhales. After this, it is to be evaporated to the 
proper degree of concentration, and left to cool. Crys- 
tals of gallic acid are deposited : these are to be sepa- 
rated by Alteration, and washed with cold water. The 
evaporation of the rest of the liquid is to be repeated, till 
all the gallic acid is obtained from it. 

The gallic acid thus obtained has a very acid taste ; 
it reddens vegetable blues, dissolves in 1^ parts of boil- 
ing water, and 12 parts of cold water. Alcohol- dissolves; 
one-fourth of its weight in the cold, and its own weight, 
if assisted by heat. 

Gallic acid thrown upon burning coals, inflames, and 
emits an aromatic odour, not very dissimilar to that of 
the benzoic acid. Its residuum is charcoal. It is decom- 
posed by distillation. It has a great affinity for most of 
the metallic oxides, which it will take from the strongest 
acids. A solution of gold it renders green, and causes a 



HYDRIODIC ACID, IODIC ACID. 171 

brown precipitate, which readily passes to the metallic 
state. On the nitric solution of silver, it has the same 
effect. Mercury, it precipitates of an orange-yellow ; 
copper, brown ; bismuth, of a lemon colour ; lead, white ; 
iron, purple, or black ; for which reason, nut-galls are 
used to form writing-ink: they are also extensively used 
in dyeing. Platina, zinc, tin, cobalt, and manganese, it 
does not precipitate. 

The combination of the gallic acid with the different 
bases, are called gallates. 

HYDRIODIC ACID. 

A GASEOUS acid in its insulated state. If 4 parts of 
iodine be mixed with one of phosphorus, in a small glass 
retort, applying a gentle heat, and adding a few drops of 
water from time to time, a gas comes over, which must 
be received in the mercurial bath. It is elastic and 
invisible, but has a smell somewhat similar to that of 
muriatic acid. Mercury after some time decomposes it, 
seizing its iodine, and leaving its hydrogen, equal to one 
half the original bulk, at liberty. Chlorine, on the other 
hand, unites to its hydrogen, and precipitates the iodine. 
From these experiments, it evidently consists of vapour 
of iodine and hydrogen, which combine in equal volumes, 
without change of their primitive bulk. Hydriodic acid 
is partly decomposed at a red heat, and' the decomposition 
is complete if it be mixed with oxygen. Water is form- 
ed and iodine separated. 

IODIC ACID. 

When barytes water is made to act on iodine, a 
soluble hydriodate, and an insoluble iodate of barytes, 
are formed. On the latter well washed, pour sulphuric 
acid equivalent to the barytes present, diluted with twice 
its weight of water, and heat the mixture. The iodic 
acid quickly abandons a portion of its base, and com- 
bines with the water; but though even less than the 



172 CHEMISTRY. 

equivalent proportion of sulphuric acid has been used, a 
little of it will be found mixed with the liquid acid. It 
we endeavour to separate this portion, by adding barytes 
water, the two acids precipitate together. 

LACCIC ACID. 

This acid is obtained from lacca^ the substance in 
which it exists. Dr. Sohn made a watery extract of 
powdered sticklac, and evaporated it to dryness. He 
digested alcohol on this extract, and evaporated the alco- 
holic extract to dryness. He then digested this mass in 
ether, and evaporated the ethereal solution ; when he 
obtained a syrup mass of a light yellow colour, which 
was again dissolved in alcohol. On adding water to this 
solution, a little resin fell. A peculiar acid united to 
potassa and lime remains in the solution, which is ob- 
tained free, by forming with acetate of lead an insoluble 
laccate, and decomposing this v^dth the equivalent quan- 
tity of sulphuric acid. Laccic acid crystallizes; it has a 
wine yellow colour, a sour taste, and is soluble as we 
have seen, in water, alcohol, and ether. It precipitates 
lead and mercury white, but it does not affect lime, 
barytes, or silver in their solutions. It throws down the 
salts of iron white. With lime, potassa, or soda, it forms 
deliquescent salts, soluble in alcohol. 

LACTIC ACID. 

This is the acid which appears in milk, that has be- 
come sour. To obtain it by Scheele's process, evaporate 
a quantity of sour whey to an eighth part, and then filter 
it ; this separates the cheesy part. Saturate the liquid 
with lime-water, and the phosphate of lime precipitates. 
Filter again, and dilute the liquid with three times its 
own bulk of water; add to it oxalic acid, drop by drop, 
to precipitate the lime which has dissolved from the lime- 
water ; then add a very small quantity of lime-water, to 
see whether too much oxalic acid has been added. If 



LITHIC OR URIC AOID, MALIC ACID. 173 

there has, oxalate of lime immediately precipitates. 
Evaporate the solution to tlie consistence of honey, pour 
in a sufficient quantity of alcohol, and filter again ; the 
acid passes through dissolved in the alcohol, but the 
sugar of milk, and every other substance, remains behind. 
Add to the solution a small quantity of water, and distil 
with a low heat; the alcohol passes over, and leaves 
behind the lactic acid dissolved in w^ater. 

Lactic acid is incapable of crystallizing ; w^hen evapo- 
rated to dryness, it deliquesces in the air. Its salts are 
called lactates, 

LITHIC OR URIC ACID. 

ScHEELE, in analyzing human calculi, found that a 
peculiar acid constituted a greater part of them all, and 
nearly the whole of some. It exists in human urine, 
from which it spontaneously separates in a few days in 
the form of red crystals with brilliant facets, the urine 
at the same time losing its colour and acid nature. It 
has neither taste nor smell, but reddens vegetable blues. 
It is soluble in 2000 times its weight of cold water. It 
is a composition of carbon, nitrogen, hydrogen, and 
oxygen. 

This acid is found in the urine of the camel, and in 
those anthritic concretions commonly called chalk-stones. 

MALIC ACID. 

This acid is obtained by saturating the juice of apples 
with alkali, pouring in the acetous solution of lead, 
until it occasions no more precipitate. The precipitate 
is then to be edulcorated, and sulphuric acid poured on 
it, until the liquor has acquired a fresh acid taste, with- 
out any mixture of sweetness. The whole is then to be 
filtered, to separate the sulphate of lead. ' The filtered 
liquor is the malic acid, which is very pure, remains 
always in a fluid state, and cannot be rendered concrete. 
15* 



174 CHEMISTRY. 

MARGARITIC ACID. 

When we immerse soap, made of pork-grease and 
potassa, in a large quantity of water, one part is dissolved, 
while the other part is precipitated in the form of seve- 
ral brilliant pellets. These are separated, dried, washed 
in a large quantity of water, and then dried on a filter : 
they are now dissolved in boiling alcohol, specific gra- 
vity 0.820; from which, as it cools, the pearly substance 
falls down pure. On acting on this with diluted muriatic 
acid, a substance of a peculiar kind, which Chevreui!, 
the discoverer, calls margarine, or margaritic acid, is 
separated. It must be well washed with water, dissolved 
in boiling alcohol ; from which it is recovered, in the same 
crystalline form, when the solution cools. 

Margaric acid is pearly white, and tasteless. Its 
smell is feeble, and a little similar to that of melted wax. 
Its specific gravity is inferior to that of water. It melts 
at 134° F., into a very limpid, colourless liquid, which 
crystallizes, on cooling, into brilliant w^hite needles, of 
the finest white. It is insoluble in water, but very solu- 
ble in alcohol, specific gravity 0.800. Cold margaric 
acid has no action on the colour of litmus ; but when 
heated so as to soften without melting, the blue was red- 
dened. It combines with the salifiable bases, and forms 
neutral compounds. Two orders of margarites are 
formed, the margarites, :\nd the super-margarites ; the 
former being converted into the latter by pouring a large 
quantity of water on them. Other fats, besides that of 
the hog, yield this substance. 

That of man is obtained under three different forms. 
1. In very fine long needles, disposed in flat stars. 2. In 
very fine and very short needles, forming waved figures, 
like those of the margaric acid of carcases. 3. In very 
large brilliant crystals, disposed in stars, similar to the 
margaric acid of the hog. The margaric acids of man 
and the hog resemble each other ; as do those of the ox 
and the sheep; and of the goose and the jaguar. The 
compounds with the bases, are real soaps. The solution 
in alcohol affords the transparent soaps of this country* 



MECONLIC, MELASSIC, AMO MELLITIC ACID. 175 

' MECONIC ACID. 

This acid is a constituent of opium. It was discovered 
by Sertuerner, who procured it in the following way : 
After precipitating the morphia^ from a solution of 
opium, by ammonia : he added to the residual fluid a 
solution of muriate of barytes. A precipitate is in this 
way formed, which is supposed to be a quadruple com- 
pound, of barytes, morphia extract, and the meconic 
acid. The extract is removed by alcohol, and the 
barytes by sulphuric acid; when the meconic acid is 
left, merely in combination with a portion of the morphia ; 
from this it is purified by successive solutions and evapo- 
rations. The acid, when subhmed, forms long colourless 
needles ; it has a strong affinity for the oxide of iron, so 
as to take it from the muriatic solutions, and form with 
it a cherry-red precipitate. It forms a crystallizable 
salt with lime, which is not decomposed by sulphuric 
acid, and what is curious, it seems to possess no particu- 
lar power over the human body, when received into the 
stomach. The essential salt of opium, obtained in 
Derosne's original experiments, was probably the meco- 
niate of morphia. 

Robiquet has made a useful modification of the pro- 
cess for extracting meconic acid. He treats the opium 
with magnesia, to separate the morphia, while meconiate 
of magnesia is also formed. The magnesia is removed 
by adding muriate of barytes, and the barytes is after- 
wards separated by dilute sulphuric acid. A larger pro- 
portion of meconic acid is thus obtained. 

MELASSIC ACID. 

The acid present in melasses, which has been thought 
a peculiar acid by some, by others the acetic. 

MELLITIC ACID. 

Klaproth discovered in the mellilite, or honey stone, 
what he conceives to be a peculiar acid of the vegetable 



176 CHEMISTRY. 

kind, combined with alumina. This acid is easily obtained 
by reducing the stone to powder, and boiling it in about 
seventy times its weight of water ; when the acid will 
dissolve, and may be separated from the alumina by 
Alteration. By evaporating the solution, it may be ob- 
tained in the form of crystals. The following are its 
characters. 

It crystallizes in fine needles or globules by the union 
of these, or small prisms. Its taste is at first a sweetish- 
sour, which leaves a bitterness behind. On a plate of 
hot metal it is easily decomposed, and dissipated in copi- 
ous grey fumes, which affect not the smell, leaving 
behind a small quantity of ashes, that do not change 
either red or blue tincture of litmus. Neutralized by 
potassa, it crystallizes in groups of long prisms: by soda, 
in cubes, or triangular laminee, sometimes in groups, some- 
times single ; and by ammonia, in beautiful prisms wdth 
six planes, which soon lose their transparency, and ac- 
quire a silver- white hue. If the metallic acid be dissolved 
in lime water, and a solution of calcined strontian. or 
barytes be dropped into it, a white precipitate is thrown 
down, which is re-dissolved on adding muriatic acid. 
With a solution of acetg^te of barytes, it produces like- 
wise a white precipitate, which nitric acid re-dissolves. 
With a solution of muriate of barytes, it produces no 
precipitate, or even cloud ; but after standing some time, 
tine transparent needly crystals are deposited. The 
metallic acid produces no change in a solution of nitrate 
of silver. From a solution of nitrate of mercury, either 
hot or cold, it throws down a copious white precipitate, 
which an addition of nitric acid immediately re-dissolves. 
With nitrate of iron it gives an abundant precipitate of 
a dun yellow colour, which may be re-dissolved by muri- 
atic acid. With a solution of acetate of lead, it produces 
an abundant precipitate, immediately re-dissolved on 
adding nitric acid. With acetate of copper, it gives a 
greyish-green precipitate ; but it does not effect a solu- 
tion of muriate of copper. Lime-water precipitated by 
it, is immediately re-dissolved on adding nitric acid. 



MENISPERMIC ACID, MOLYBDIC ACID. 177 

MENISPERMICACID. 

The seeds of menispermune oculus, being macerated 
for 24 hours, in 5 tinnes their weight of water, first cold, 
and then boiling hot, yield an infusion, from which solu- 
tion, sub-acetate of lead throws down a menispermate 
of lead. This is to be washed and drained, diffused 
through water, and decomposed by a current of sulphu- 
retted hydrogen gas. The liquid thus freed from lead, 
is to be deprived of sulphuretted hydrogen by heat, and 
then forms solution of menispermic acid. By repeated 
evaporations and solutions in alcohol, it loses its bitter 
taste, and becomes a purer acid. It occasions no precip- 
itate with lime-water ; with nitrate of barytes it yields a 
grey precipitate ; with nitrate of silver, a deep yellow ; 
and with sulphate of magnesia, a copious precipitate. 

MOLYBDIC ACID, 

MoLYBDiG acid is obtained from the ore or sulphuret 
of molybdenum, by distilling nitric acid off it repeatedly, 
till the sulphur and metal are both acidified, which is 
known by the conversion of the whole into a white mass. 
Hot water carries off the sulphuric acid, and leaves the 
molybdic acid in a state of purity. 

Molybdic acid is a yellowish-w^hite powder ; it has an 
acrid but metallic taste. It is not altered in the air, and 
will bear a strong heat if the crucible be covered ; but 
if the crucible be uncovered, the acid rises in the form 
of a white smoke. Its specific gravity is 3.75. It re- 
quires 570 times its weight of water to dissolve it. The 
solution has a sour taste, coagulates solutions of soap, and 
precipitates alkaline sulphurets. Paper dipped in this 
acid beconjes of a beautiful blue colour in the sun. 

The molybdic acid has not been applied to any use in 
the arts, though experiments have been made which indi- 
cate that it may become useful in dyeing. Its combina- 
tions with different bases are called molybdates. 



178 CHEMISTRY. 

MOLYBDENOUS ACID. 

MoLYBDENA is susceptiblc of four different combinations 
with oxygen ; at the lowest it is in a state of black oxide; 
at the next it is blue ; at the third it begins to assunne 
acid properties, and is green. This is the molyhdenous 
acid. The next dose of oxygen fornfis the yellowish 
white powder, which is the acid treated of in the last 
section. 

MUCIC ACID. 

This acid has been generally known by the name of 
saccholactic, because it was first obtained from sugar of 
milk ; but as all the gums appear to afford it, and the 
principal acid in the sugar of milk is the oxalic, chemists, 
in general, now distinguish it by the name of mucic acid. 

It was discovered by Scheele. Having poured twelve 
ounces of diluted nitric acid on four ounces of powdered 
sugar of milk, in a glass retort on a sand bath, the mix- 
ture became gradually hot, and at length effervesced 
violently, and continued to do so for a considerable time 
after the retort was taken from the fire. It is necessary 
therefore, to use a large retort, and not to bite the 
receiver too tight. The effervescence having nearly 
subsided, the retort was again placed on the sand heat, 
and the nitric acid distilled off, till the mass had acquired 
a yellowish colour. This exhibiting no crystals, eight 
ounces more of the same acid were added, and the 
distillation repeated, till the yellow colour of the fluid 
disappeared. As the fluid was inspissated by cooling, it 
was re-dissolved in eight ounces of water, and filtered. 
The filtered liquor held oxalic acid in solution, and seven 
drachms and a half of white powder remained on the 
filter. This powder was the acid under consideration. 

If one part of gum be heated gently with two of nitric 
acid, till a small quantity of nitrous gas and carbonic 
acid is disengaged, the dissolved mass will deposit on 
cooling the mucic acid. According to Fourcroy and 
Vanquelin, different gums yield from 14 to 26 hundredths 
of this acid. 



MURIATIC ACID. 179 

This pulverulent acid is soluble in about sixty parts of 
hot water, and by cooling, a fourth part separates in 
snnall shining scales, that, grow white in the air. It de- 
composes the nnuriate of barytes, and both the nitrate 
and muriate of lime. It acts very little on the metals, 
but forms with their oxides salts scarcely soluble. It 
precipitates the nitrate of silver, lead, and mercury. 
With potassa it forms a salt soluble in eight parts of 
boiling water, and crystallizable by cooling. That of 
soda requires but five parts of water, and is equally 
crystallizable. Both these salts are still more soluble 
when the acid is in excess. That of ammonia is deprived 
of its base by heat. The salts of barytes, lime, and 
magnesia are nearly insoluble. 

MURIATIC ACID. 

Muriatic acid, so generally known under the name of 
spirit of salt, or marine acid, is a combination of oxy- 
gen with an unknown base ; for the acid has never been 
decomposed. 

In its combinations it is very abundant in the mineral 
kingdom, particularly with soda, lime, and magnesia. Its 
combination with soda forms common salt, and the affinity 
of the two substances is such, that they are not separated 
by a heat w^hich volatilizes ^salt. In obtaining this acid 
from muriate of soda, therefore, some substances must 
be used which will combine with the alkali. Sulphuric 
acid, or substances which contain it, such as clay, are 
generally used. Mix one part of sulphuric acid with 
two parts of dry muriate of soda, in a glass retort, apply 
a gentle heat, and use the mercurial pneumatic trough 
to collect the product which comes over. The product 
is muriatic acid in a state of gas. This gaseous acid is 
invisible, and elastic, like common air, but has about 
twice its specific gravity. It has a pungent, suffocating 
smell, and it is extremely caustic. 

Muriatic acid gas absolves water with avidity. Water 
will combine with its weight of the gas, and the specific 



180 CHEMISTRY. 

gravity of the liquid muriatic acid thus obtained is 1.5 : 
it is, however, not easily procured and preserved of a 
greater specific gravity than 1.196. 

Liquid muriatic acid is generally of a pale yellow 
colour, but this colour is attributed to the presence of 
some impurity ; it preserves the smell of the gas, is very 
volatile, and gives out white fumes by exposure to the 
atmosphere. 

It is capable, by the assistance of heat, of oxidizing 
iron, tin, lead, zinc, bismuth, cobalt, nickel, manganese, 
antimony, and arsenic. At a boiling heat, it oxidizes 
silver and copper. On gold, platina, mercury, tungsten, 
molybdenum, tellurium, and titanium, it has no action. 

The proper solvent for gold and platina, is the nitro- 
muriatic acid, composed of one part of muriatic, and 
two of nitric acid. 

Muriatic acid is the best test for silver. A single drop 
of it poured into a solution containing this metal will 
cause a copious precipitate. 

Muriatic acid, combined With different bases, forms the 
salts called muiiates. 

This acid, in the state of gas, has a powerful effect in 
neutralizing putrid effluvia. Morveau, by pouring two 
pounds of sulphuric acid upon six pounds of common 
salt, and having the mixture on a common house furnace 
of live coal, completely destroyed the putrid exhalations 
which had caused the cathedral of Dijon to be deserted. 

NITRIC ACID. 

Nitric acid is formed by the chemical union of about 
25 parts by weight of nitrogen, with 75 parts of oxygen. 
By mixing nitrogen and oxygen in these proportions, 
and passing a number of electrical shocks through the 
mixture, nitric acid is produced. In other words, the 
combustion of nitrogen produces nitric acid. 

Nitric acid, combined with potass, form the salt called 
nitrate of potass, or saltpetre, and it is by the decom- 
position of this salt, that it may be procured. If three 



NITRIC ACID. 181 

parts of nitrate of potass, with one of sulphuric acid, be 
distilled, the nitric acid, mixed with a small proportion 
of nitrous, comes over. The nitrous acid may be expel- 
led by a gentle heat. Nitric acid is clear and colourless, 
like water ; it corrodes animal substances, and stains the 
human skin a permanent yellow. Its smell is remark- 
ably pungent, and its taste strongly acid ; in short, it 
eminently possesses all the properties enumerated as 
peculiar to acids. The action of light alone will, how- 
ever, separate a part of its oxygen, and cause it to 
assume a yellow colour. 

Nitric acid has a strong affinity for water, and has 
never been obtained except in combination with it. 
When concentrated, it attracts moisture from the atmo- 
sphere, but not so powerfully as the sulphuric acid. 
When mixed with water, it produces heat, but not in 
equal degree with the sulphuric acid. It boils at 248"^. 
When concentrated to the utmost, its specific gravity is 
about 1.5. When diluted with water, it is sold under 
the name of aquafortis : even the double aquafortis of 
the stores sold is only about half the strength of nitric 
acid. 

Nitric acid is easily decomposed, and it therefore con- 
stitutes a valuable agent to the chemist. It is capable 
of oxidizing all the metals, except gold and titanium; 
and even gold it appears to attack in a slight degree. 
If brought into contact with hydrogen at a slight tem- 
perature, a violent detonation is produced. If mixed 
with oils, it sets them on fire, and both the acid and the 
oil is decomposed. The oils should be iree from water, 
but as this is rarely the case, the experiment is most cer- 
tain of success if a little sulphuric acid be mixed with 
the nitric acid, as that acid will combine with the water. 
Oils deprived of water by boiling, inflame with nitric 
acid alone. In making these mixtures, the operator 
should keep himself at a distance from them, by using 
vessels with long handles. 

Perfectly dry charcoal is also inflamed by nitric acid : 
with dry filings of iron the same effect takes place ; and 
16 



182 CHEMISTRY. 

also with zinc, and tin, if the acid be poured upon them 
in fusion. 

The nitric acid, with the alkalies, alkaline earths, alu- 
mine, .zircon, and the oxides of metals, form the salts 
called nitrates, 

NITROUS ACID. 

According to the principles of the new nomenclature, 
there is no acid strictly entitled to the appellation of ni- 
trous acid : the acid which obtains this name is not the 
acid of nitre with a minimum of oxygen, but nitric acid, 
combined with different proportions of nitric oxide ; of 
which an account will be found under the head of 
oxides. 

Nitrous acid is more or less coloured, according to the 
quantity of nitric oxide with which it is impregnated. It 
parts with the gas very readily; which, when in quan- 
tity, passes off in vapours that assume a red colour on 
mixing wnth the atmosphere. On account of the extri- 
cation of these vapours, the acid is sometimes called 
fuming aquafortis. The addition of different portions of 
water causes nitrous acid to appear blue, green, yellow, 
&c. ; but the vapours are always of the same red hue. 

The general properties of nitrous acid are similar to 
those of the nitric; with different bases, it forms the 
salts called nitrates. These are not formed by the di- 
rect union of their component parts ; but by exposing 
nitrates to a high temperature, which, separating a part 
of their oxygen, leaves them in the state of nitrates. 

NITROLEUCIC ACID. 

This acid is so named from its being obtained by the 
action of nitric acid on leucine. Leucine is capable of 
uniting to nitric acid, and forming a compound, which 
Braconnet has called the nitroleucic acid. When we 
dissolve leucine in nitric acid, and evaporate the solution 
to a certain point, it passes into a crystalline mass, with- 
out any disengagement of nitrous vapour, or of any 



NITRO-MURIATIC, NITRO-SULPHURIC, OLEIC. 183 

gaseous matter. If we press this mass between blotting- 
paper, and dissolve it in water, we shall obtain from 
this, by concentration, fine divergent, and nearly colour- 
less needles. These constitute the new acid. It unites 
to the bases, forming salts which fuse on red-hot coals. 
The nitro-leucates of lime and magnesia are unalterable 
in the air. 

NITRO-MURIATIC ACID. 

Aqua regia. When nitric and muriatic acids are 
mixed, they become yellow, and acquire the power of 
readily dissolving gold, which neither of the acids pos- 
sessed separately. This mixture evolves chlorine, a par- 
tial decomposition of both acids having taken place ; and 
water, chlorine, and nitrous acid gas are thus produced : 
that is, the hydrogen of the muriatic acid abstracts oxy- 
gen from the nitric, to form water. The result must be 
chlorine and nitrous acid. 



JVITRO-SULPHURIC ACID. 

A COMPOUND consisting of one part of nitre dissolved 
in about ten of sulphuric acid. 

OLEIC ACID. 

When potassa and hogs' lard are saponified, the mar- 
garate of the alkali separates in the form of a pearly- 
looking solid, while the fluid fat remains in solution, 
combined with the potassa. When the alkali is sepa- 
rated by tartaric acid, the oily principle of fat is ob- 
tained, which Chevreuil purifies by saponifying it again, 
and again recovering it two or three times ; by which 
means the whole of the margarine is separated. As this 
oil has the property of saturating bases, and forming 
neutral compounds, he has called it oleic acid. 



184 CHEMISTRY. 

OXALIC ACID. 

The oxalic acid exists in the juice of the wood-sorrel, 
combined with potass. When prepared from this plant, 
it is sold under the name of salt of lemons; and is used 
as a substitute for the real juice of lemons. Sugar, and 
all other saccharine substances, contain the radical of 
the very same acid which wood-sorrel affords. It may 
be extracted from sugar in the following manner : 

To six ounces of nitric acid, in a tubulated retort, to 
w^hich a large receiver is luted, add, by degrees, one 
ounce of lump sugar, coarsely powdered. A gentle heat 
may be applied during the solution, and nitric oxide will 
be evolved in abundance. When the whole of the 
sugar is dissolved, distil off a part of the acid, till what 
remains in the retort has the consistence of a syrup, 
and this will form regular crystals, amounting to 58 
parts from 100 of sugar. These crystals may be dis- 
solved in water, re-crystallized, and dried on blotting- 
paper. 

Honey, gum arabic, alcohol, the calculous concre- 
tions in the kidneys and bladders of animals, silk, wool, 
hair, and various other bodies, afford oxalic acid, by 
distillation with nitric acid. Berthollet observes, that 
the quantity of the acid afforded by vegetable matters 
is in proportion to their nutritive qualities. 

The crystals of oxalic acid effloresce in dry air, but 
attract a little humidity if it be damp. They are solu- 
ble in one part of hot, and two parts of cold water ; and 
are decomposed by a red heat. When dissolved in 
3600 times their weight of water, the solution still red- 
dens litmus-paper, and is perfectly acid to the taste. 

The oxalic acid is a good test for lime, for which it 
has a greater affinity than any other acid. It forms with 
lime, an insoluble salt, not decomposable except by fire, 
and turning syrup of violets green. 

Oxalic acid is capable of oxaiizing lead, copper, iron, 
tin, bismuth, nickel, cobalt, zinc, and manganese. 

The combination of oxalic acid with the alkalies and 
other bases, form the salts called oxalates. 



OXYMURIATIC ACID. 185 

Oxalic acid dissolved in water is employed by calico 
printers to destroy or lighten colours which are produced 
by iron. It is also used to remove iron moulds, and to 
take out spots of ink from furniture, and various other 
articles, which it does with the greatest facility. The 
crystals of oxalic acid much resemble those of Epsom 
salt which are much used as a purgative: several unfor- 
tunate accidents have happened through its having been 
taken by mistake, as the corrosive power of this acid is 
very great, when taken in so large a dose as Epsom salt. 

OXYMURIATIC ACID. 

If 84 parts of muriatic acid be combined with 16 of 
oxygen, they form oxymuriatic acid. This combination 
is usually formed by adding to one part of the black ox- 
ide of manganese, two parts of strong muriatic acid, and 
distilling the mixture with a gentle heat. The gas ob- 
tained is received over water, by means of pneumatic 
apparatus. 

Oxymuriatic acid gas is tinged of a yellow colour by 
contact with atmospheric air; it supports flame, but 
cannot be breathed without the most injurious effects. 
Pelletier having attempted to respire it, the consequence 
was a consumption, which in a short time put a period 
to his life. If it happen to be accidentally inhaled, the 
vapour of volatile alkali, for which it has a strong affinity, 
is the best remedy. It does not readily unite with water; 
and at the temperature of freezing water it crystaUizes. 

Other acids become more intensely sour by an ad- 
ditional dose of oxygen, but the muriatic has this pro- 
perty diminished by the same addition. The taste of 
oxymuriatic acid is harsh and styptic, and instead of 
reddening vegetable colours, it changes them all to white, 
and their colours cannot be restored either by acids or 
alkalies. On this account, it has been extensively used 
in the process of bleaching. After having thus been 
employed upon a sufficient quantity of materials, it is 
16* 



186 CHEMISTRY. 

converted into common muriatic acid. It has, therefore, 
produced its effect by imparting oxygen. 

As the oxymuriatic acid eradicates writing-ink, but 
has no effect upon printing-ink, it may be conveniently 
used for whitening soiled books and prints; it removes 
all stains but those of an oily nature. An easy mode of 
preparing a quantity of it, consists in adding one ounce 
of the red oxide of lead to three ounces of muriatic. 
The red lead supplies the oxygen which oxygenizes the 
acid. This preparation should noti)e made till near the 
time against which it is wanted, and when made it 
should be kept in the dark, as it is deoxvgenized bv the 

The nitromuriatic and oxymuriatic acids have the 
same appearance and odour, as well as the same effects, 
as solvents. It appears, therefore, that the nitric acid, 
when added to the muriatic, has only the effect of sup- 
plying it with oxygen. 

Oxymuriatic acid oxidizes nearly all the metals with- 
out the assistance of heat. It decomposes the red sul- 
phuret of mercury, which neither the sulphuric nor the 
nitric acid will accomplish. It may be combined with a 
great number of bases ; the salts which it forms detonate 
v/ith carbon and several metallic substances. 

Hyper-oxymuriate of potass is made by introducing 
the oxymuriatic acid gas into a solution of potass; its crys- 
tals, as well as those of common muriate, being formed 
by evaporation in the dark. It gives a faint taste, with 
a sensation of coldness in the mouth ; the crvstals have 
somewhat of a silvery appearance, and emit light by 
attrition. It is decomposed by the action of light, part- 
ing with oxygen, and becoming simple muriate of potass. 
Heat also separates its oxygen in the form of gas ; 100 
grains of it will yield 75 cubic inches of oxygen gas. 

When three parts of hyper-oxymuriate of potass, and 
one of sulphur, are triturated in a mortar, the mixture 
detonates violently. The same effect is produced when 
the mixture is struck with a hammer upon an anvil. 

Phosphorus and hyper-oxymuriate of potass detonate 
with prodigious force. 



PHOSPHORIC ACID. 187 

Exotic seeds which could not be caused to germinate 
by ordinary means, have germinated after being steeped 
for a few days in weak oxymuriatic acid. 

PHOSPHORIC ACID. 

The purest phosphoric acid is obtained by the com- 
bustion of phosphorus in oxyc^en gas. If no moisture be 
present, it is obtained in the form of white flocks, which 
are very Hght, and have a strongly acid taste. These 
flocks will attract moisture from the atmosphere, and 
become a fluid acid. This acid may be concentrated 
till its specific gravity exceeds that of the sulphuric 
acid ; though strongly acrid, it is not corrosive, and has 
no smell. 

Phosphoric acid may likewise be obtained by heating 
phosphorus with nitric or sulphuric acid ; it remains in 
the retort, after these acids are driven over. Another 
mode of forming it, consists in exposing phosphorus for 
some wrecks to the common temperature of the atmo- 
sphere, by which means it is gradually converted into a 
liquid acid. It is usually placed on the inclined side of a 
funnel, through which the liquid which is formed drops 
into a bottle placed beneath to receive it, and contain- 
ing a little distilled water. The acid thus prepared, is 
called phosphoric acid by deliquescence. 

The quantity of acid obtained from phosphorus, is 
generally about three times the weight of the phos- 
phorus used. 

If phosphoric acid be exposed to heat, it gradually 
becomes thick and glutinous ; and if the heat be con- 
tinued, it melts into a kind of glass, which is called the 
glacial acid of phosphorus, or glacial phosphoric acid. 
This glacial acid becomes liquid by exposure to the 
atmosphere. 

Phosphoric acid, w4ien perfectly dry, sublimes in close 
vessels, but the addition of water deprives it of this pro- 
perty. If mixed with charcoal, or other inflammable 
matter, and exposed to a strong heat, it parts with its 
oxygen, and is converted into phosphorus. 



188 CHEMISTRY. 

Phosphoric acid, assisted by heat, has some action 
upon silex, and will, therefore, decompose glass. 

The salts of phosphorus are called phosphates. The 
phosphate of lime exists in bones, from which phospho- 
rus is generally prepared. Whole mountains of phos- 
phate of lime are said to exist in the province of Estre- 
madura, in Spain. 

PHOSPHOROUS ACID. 

The spontaneous combustion of phosphorus at the 
temperature of the atmosphere, forms, in the first in- 
stance, phosphorous acid, which contains less oxygen 
than the phosphoric ; but, as phosphorous acid acquires 
an additional quantity of oxygen from the atmosphere, 
it is speedily converted into the phosphoric. 

Phosphorous acid is, therefore, very little known. It 
may, therefore, be decomposed by charcoal ; but cannot 
be reduced to the glacial state. Its salts are called 
phosphates, 

PRUSSIC ACID. 

This acid exists, combined with iron, in the fine blue 
pigment, well known by the name of Prussian blue. It 
may be obtained as follows : mix four ounces of Prussian 
blue with two of red ojcide of mercury, prepared by ni- 
tric acid, and boil them in twelve ounces, by weight, of 
water, till the whole becomes colourless; filter the liquor, 
and add to it one ounce of clean iron filings, and six or 
seven drachms of sulphuric acid : drain ofT, by distillation, 
about a fourth of the liquor, which will be prussic acid ; 
though, a3 it is liable to be contaminated w^th a portion 
of sulphuric acid, to render it pure, it may be rectified 
by re-distilling it oflf carbonate of lime. 

The prussic acid has a smell like that of peach blos- 
soms. Its taste is at first sweetish, then acid and hot, 
and it excites coughing. It is very volatile, and capable 
of existing in an acid in the gaseous form. 

The prussic acid combines with earths, alkalies, and 



PRUSSIC ACID. 189 

metallic oxides, forming the salts called prussiates. The 
prussiate of potash and iron, often called the prussian 
alkali, is one of the most important of these compounds, 
both for its utility as a test, and for making prussian blue. 
To form it, two parts of bullock's blood, and one of 
potash, are calcined by a moderate heat in a covered 
crucible, containing a hole in the lid. The calcination 
is to be discontinued when the matter ceases to afford a 
small blue flame. The residuum must be lixiviated with 
a small quantity of cold water. In this state, the prus- 
siate of potass may be employed for making prussian 
blue, though not pure enough for the use of the chemist. 
Henry recommends it to be obtained by the following 
process from prussian blue, when required quite pure : 
To a solution of potass, deprived of its carbonic acid by 
quick-lime, and heated nearly to the boiling point, add 
by degrees powdered prussian blue, till its colour ceases 
to be discharged. Filter the liquor, w^ash the sediment 
with water, till it ceases to extract any thing, mix the 
washings together, and pour the mixture into an earthen 
dish in a sand-heat. When the solution has become hot, 
add a little diluted sulphuric acid, and continue the heat 
about an hour. A copious precipitate of prussian blue 
will be formed, which must be separated by Alteration. 
Assay a small quantity of the filtered liquor in a wine- 
glass, with a little diluted sulphuric acid. If an abundant 
production of prussian blue still take place, the whole 
liquor must be exposed again to heat with a little diluted 
sulphuric acid, and this must be repeated as often as is 
necessary. Into the liquor thus far purified, pour a solu- 
tion of sulphate of copper in four or six times its weight 
of warm water, as long as a reddisli brown precipitate 
continues to appear. Wash the precipitate, which is a 
prussiate of copper, with repeated eflfusions of warm 
water; and when the v/ater comes off^ colourless, lay the 
precipitate on a linen filter to drain, after which it may 
be dried on a chalk-stone. When the precipitate is dry, 
powder it, and add it by degrees to a solution of potass, 
which will take the prussic acid from the oxide of copper. 



190 CHEMISTRY. 

This prussiate of potass, however, will be contaminated 
by some portion of sulphate of potass, from part of 
which it may be freed by gentle evaporation, as the sul- 
phate crystallizes first. To the remaining liquor, add a 
solution of barytes in warm water, as long as a white 
precipitate ensues, observing not to add more after its 
cessation. The solution of prussiate of potass will now 
be freed in a great measure from iron, and entirely from 
sulphate, and by gentle evaporation, will form, on cooling, 
beautiful crystals. These, dissolved in cold \yater, afford 
the purest prussian alkali that can be prepared. If 
pure barytes be not at hand, acetate of barytes may be 
used instead ; as the acetate of potavss formed, not being 
crystallizable, wdll remain in the mother-water. 

Prussiates of soda and of ammonia may be prepared 
in a similar way to the prussiate of potass, above de- 
scribed. 

PYROLIGNEOUS ACID. 

In the destructive distillation of wood, an acid is 
obtained, which was formerly called acid spirit of wood, 
and since pyroligneous acid. Fourcroy and Vanquelin 
showed that this acid was merely the acetic contamina- 
ted with empyreumatic oil and bitumen. 

Monge discovered, that this acid has the property of 
preventing the decomposition of animal substances. Mr. 
Wm. Dinsdale, of Field Cottage, Colchester, three years 
prior to the date of Monge's discovery, did propose to 
the Lord Commissioners of the Admiralty, to apply a 
pyroligneous acid, prepared out of the contact of iron 
vessels, which blacken it, to the purpose of preserving 
animal food, wherever their ships might go. As this 
application may in many places afford valuable anti- 
scorbutic articles of food, and thence might be eminently 
conducive to the health of seamen ; it is to be hoped 
that Mr. Dinsdale's ingenious plan might be carried into 
effect, as far as is deemed necessary. It is sufficient to 
plunge meat for a few moments into this acid, even 
blightly empyreumatic, to preserve it as long as you 



PYROLIGNEOUS ACID. 191 

please. Putrefaction, it is said, not only stops hut retro- 
grades. To the empyreumatic oil a part of this effect 
has been ascribed ; and hence has been accounted for, 
the agency of smoke in the preservation of tongues, 
hams, herrings, &c. Dr. Jorg, of Leipsic, has entirely 
recovered several anatomical preparations from incipient 
corruption by pouring this acid over them. With the 
empyreumatic oil or tar he has smeared pieces of flesh 
already advanced in decay, and notwithstanding that the 
weather was hot, they soon became dry and sound. Mr. 
Ramsey has added the following facts in the 5th number 
of the Edinburgh Philosophical Journal. If fish be sim- 
ply dipped in redistilled pyroligneous acid, of the specific 
gravity 1.012, and afterwards dried in the shade, they 
preserve perfectly well. On boiling herrings treated in 
this manner, they were very agreeable to the taste, and 
had nothing of the disagreeable empyreuma which those 
of his earlier experiments had, which were steeped for 
three hours in the acid. A number of very fine had- 
docks were cleaned, split, and slightly sprinkled with salt 
^r six hours. After being drained, they were dipped for 
about three seconds in pyroligneous acid, then hung up 
in the shade for about six days. On being broiled, the 
fish were of an uncommon fine flavour, and delicately 
white. Beef treated in the same way, had the same 
flavour as the Hamburgh beef, and kept as w^ell. Mr. 
Ramsey has since found, that his perfectly purified vine- 
gar, specific gravity 1.034, being applied by a cloth or 
spunge to the surface of fresh meat, makes it keep sweet 
and sound for many days longer in summer, than it other- 
wise would. Immersion for a minute in his purified 
common vinegar, specific gravity 1.009, protects beef and 
fish from all taints in summer, provided they be hung up 
and dried in the shade. When by frequent use the 
pyroligneous acid has become impure, it may be clarified 
by beating up 20 gallons of it with a dozen of eggs in 
the usual manner, and heating the mixture in an iron 
boiler. Before boiling, the eggs coagulate, and bring the 
impurities to the surface of the boiler, and are of 



192 CHEMISTRY. 

course to be carefully skimmed ofE The acid must be 
immediately withdrawn from the boiler, as it acts on 
iron. 

This acid has long been prepared for the calico-print- 
ers. The following arrangement of apparatus has been 
found to answer very well. A series of cast-iron cylin- 
ders, about four feet diameter, and six feet long, are set 
in pairs, horizontally, in brick-work, so that the flame 
of one fire may play round both. Both ends project a 
little from the brick-work: one of them has a cast-iron 
plate well fitted, and firmly bolted isb it, from the centre 
of which, an iron pipe, about six inches in diameter, 
proceeds, and enters, at a right angle, the main cool- 
ing-pipe. The diameter of this main pipe may be from 
9 to 14 inches, according to the number of cylinders. 
The other end of the cylinder is called the mouth of the 
retort. This is closed by an iron plate, smeared round 
its edge with clay, and secured in its place by wedges. 
The charge of wood for such cylinders is about 8 cwt. 

The hard woods, oak, ash, birch, and beech, are alone 
used; but fir does not answer. The heat is kept up 
during the day-time, and the furnace is allowed to cool 
during the night. Next morning, the door is opened, the 
charcoal is removed, and a new charge of wood is intro- 
duced. The average product of wood vinegar, or raw 
pyroligneous acid, is thirty-five gallons. It is much con- 
taminated with tar, is of a deep brown colour, and has a 
specific gravity of 1.025; so that its weight is about 3 
cwt. ; but the residuary charcoal is found to weigh no 
more than one-fifth of the wood employed. 

The raw pyroligneous is rectified by a second distilla- 
tion in a copper-still, in the body of which, about 20 gal- 
lons of viscid tarry matter is left from every 100 of 
vinegar, and then passes over a transparent, but brown 
vinegar, having a considerable smell, and its specific 
gravity is 1.013. Its acid powers are superior to those 
of the best wine or malt vinegar, in the proportion of 
three to two. 



RUCUMIC, ROSACIC, AND SEBACIC ACID. 193 

RUCUMIC ACID. 

Apr acid said to be peculiar to rhubarb, but not yet 
sufficiently examined. 

ROSACIC ACID. 

There is deposited from the urine of persons labour- 
ing under gout and inflammatory fevers, a sediment of a 
rose colour, occasionally in reddish crystals. It was at 
first discovered to be a peculiar acid by M. Proust, and 
afterwards examined by M. Vanquelin. This acid is 
solid, of a lively cinnabar hue, without smell, with a 
faint taste, but reddening litmus very sensibly. On 
burning coal it is decomposed into a pungent vapour, 
which has not the odour of burning animal matter. It is 
very soluble in water, and even softens in the air. It is 
soluble in alcohol. It forms soluble salts with potassa, 
soda, ammonia, barytes, strontites, and lime. It gives a 
slight rose-coloured precipitate, with acetate of lead. It 
also combines with lithic acid, forming so intimate a 
union, that the lithic acid in precipitating from urine, 
carries the other, through a deliquescent substance, down 
along with it. It is obtained pure by acting on the sedi- 
ment of urine with alcohol. 

SEBACIC ACID. 

Subject to a considerable heat 7 or 8 pounds of hog's 
lard, in a stone-ware retort capable of holding double 
the quantity, and connect its beak by an adopter with a 
cooled receiver. The condensible products are chiefly 
fat, altered by the fire, mixed with a little acetic and 
sebacic acids. Treat this product with boiling water 
several times, agitating the liquor, allowing it to cool, and 
decanting each time. Pour at last into the watery liquid, 
solution of acetate of lead in excess. A white flocculent 
precipitate of sebate of lead will instantly fall, which 
must be collected on a filter, washed and dried. Put the 
17 



194 CHEMISTRY. 

sebate of lead into a phial, and pour upon it its own 
weight of sulphuric acid, diluted with five or six times 
its own weight of water. Expose this phial to the heat 
of about 212^ The sulphuric acid combines with the 
oxide of lead, and sets the sebacid acid at Hberty. Filter 
the whole while hot. As the liquid cools, the sebacid 
acid crystallizes, which must be washed, to free it from 
the adhering sulphuric acid. Let it then be dried at a 
gentle heat. 

The sebacid acid is inodorous ; its taste is slight, but 
it perceptibly reddens litmus paper ; its specific gravity 
is above that of water, and its crystals are small white 
needles of little coherence. Exposed to heat, it melts 
like fat, is decomposed, and partially evaporated. The 
air has no eflfect upon it. It is much more soluble in hot 
than in cold water ; hence boiling water saturated with 
it, assumes a nearly solid consistence on cooling. Alco- 
hol dissolves it abundantly at the common temperature. 

With the alkalies it forms soluble neutral salts: but 
if we pour into them concentrated solutions, sulphuric, 
nitric, or muriatic acids, the sebacic is immediately 
deposited in large quantity. It affords precipitates with 
the acetates and nitrates of lead, mercury, and silver. 

Such is the account given by Thenard of this acid. 

SELINIC ACID. 

If selinium be heated to dryness, it forms, with nitric 
acid, a volatile and crystallizable compound, called se- 
linic acid, which unites to some of the metallic oxides, 
producing salts called seleniates. 

SORBIC ACID. 

From sorbusj the mountain-ash, from the berries of 
which it is obtained. The acid of apples, called malic, 
may be obtained most conveniently, and in the greatest 
purity, from the berries of the mountain-ash, called sor- 
bus J or pyrus aucuparia ; and hence, the present name, 



feORBIC ACID. 195 

sorbic acid. This was supposed to be a new and pecu- 
liar acid by Donovan and Vanquelin, who wrote good 
dissertations upon it But it now appears, that the sorbic 
and pure malic acids are identical. 

Bruise the ripe berries in a mortar, and then squeeze 
them in a linen bag. They yield nearly half their 
weight of juice, of the specific gravity of 1.077. This 
viscid juice, by remaining for about a fortnight in a 
warm temperature, experiences the vinous fermenta- 
tion, and would yield a portion of alcohol. By this 
change, it has become bright, clear, and passes easily 
through the filter, while the sorbic acid itself is not al- 
tered. Mix the clean juice with a filtered solution of 
acetate of lead, separate the precipitate on a filter, and 
wash it with cold water. A large quantity of boiling 
water is then to be poured upon the filter, and allowed 
to drain in glass jars. At the end of some hours, the 
solution deposits crystals of great lustre and beauty. 
Wash these with cold water, dissolve them in boiUng 
water, filter, and crystallize. Collect the new crystals, 
and boil them for half an hour in two or three times 
their weight of sulphuric acid, specific gravity of 1.090, 
supplying water as fast as it evaporates, and stirring 
the mixture diligently with a glass rod. The clear 
liquor is to be decanted into a tall, narrow glass jar, 
and, w^hile still hot, a stream of sulphuretted hydrogen 
is to be passed through it. When the lead has been all 
thrown down in a sulphuret, the liquor is to be filtered, 
and then boiled in an open vessel, to dissipate the ad- 
hering sulphuretted hydrogen. It is now a solution of 
sorbic acid. When it is evaporated to the consistence 
of a syrup, it forms mamelated masses, of a crystalline 
structure. It still contains considerable water, and de- 
liquesces when exposed to the air. Its solution is trans- 
parent, colourless, void of smell, but powerfully acid to 
the taste. Lime and barytes waters are not precipitated 
by solution of the sorbic acid, although the sorbate of 
lime is nearly insoluble. One of the most characteristic 
properties of this acid is the precipitate which it gives 



196 CHEMISTRY. 

with the acetate of lead, which is at first white and 
flocculent, but afterwards assumes a brilliant, crystal- 
line appearance. With potassa, soda, and ammonia, 
it forms crystallizable salts, containing an excess of acid, 

STANNIC ACID. 

A NAME which has been given to the peroxide of tin, 
because it is soluble in alkalies. 

SUCCINIC ACID. 

This acid is obtained from amber, which is a brown, 
transparent, combustible substance, dug out of the 
earth, in some countries, and found upon the sea-coast, 
in others. 

During the distillation of amber, the crystals of this 
acid attach themselves to the neck of the retort. They 
were formerly called salt of amber. When purified 
by repeated solution in hot water, filteration, and re- 
crystallization, they are white, shining, triangular prisms. 
Their taste is slightly acid: they redden tincture of lit- 
mus, but have no effect on syrup of violets. 

This acid obtains its name from succinu7n, the Latin 
name of amber. Its salts are called succinates, 

SUBERIC ACID. 

This acid exists in cork. It is obtained by distilling 
nitric acid of cork grated to powder, till the cork ac- 
quires the consistence of a wax, and no more red fumes 
appear. The residuum is placed in a sand-heat, and 
continually stirred, till white penetrating vapours appear. 
It is then removed from the sand-heat, and stirred till 
cold. Boiling water is poured upon the product; heat 
is applied till it liquifies, and it is then filtered. A sedi- 
ment is deposited, which must be separated by the filter, 
and the fluid evaporated nearly to dryness. The mass 
thus obtained is the suberic acid. It may be further 



SULPHURIC ACID. 197 

purified by saturating it with potass, and precipitating it 
by means of an acid ; or by boiling it along with char- 
coal powder. 

Suberic acid is not crystallizable ; boiling water dis- 
solves half its weight of it, but it is nearly insoluble in 
cold water. Its taste is acid, and slightly bitter. It 
reddens most vegetable blues, but has the peculiar prop- 
erty of changing the solution of indigo in sulphuric acid 
to a green. 

It attracts moisture from the atmosphere, and exposure 
to light renders it brown. It has no action on gold or 
nickel, but oxidixes most of the other metals. With 
different bases, its salts are called suberates, 

SULPHURIC ACID. 

Sulphuric acid is the union of oxygen and sulphur, in 
which the proportion of sulphur is, according to Berthollet, 
63.2, and that of oxygen 36.8. 

Sulphuric acid is strongly corrosive and destitute of 
colour and smell. It may be rendered twice the weight 
of water, but its customary specific gravity seldom ex- 
ceeds 1.8. When concentrated only to 1.7, it will freeze 
sooner than water, but not if either more or less concen- 
trated. This was discovered by Keir, Sulphuric acid 
is so intensely acidulous, that though diluted with 7000 
times its weight of water, its taste is still distinguishable. 

Sulphuric acid was formerly procured by distillation 
from the salt which, previous to the adoption of the new 
nomenclature, was called green vitriol ; on this account, 
and its having in some measure an oUy consistence, it 
was called oil of vitriol. At present, it is furnished for 
the demand of trade, by burning sulphur in close cham- 
bers, v/ith the addition of nitrate of potass to supply 
oxygen. The floor of the chamber is covered by a 
leaden cistern, containing water, by which the vapours 
of the sulphur are attracted and condensed. This pro- 
cess does not furnish the acid in a state of purity ; but 
at least communicates to it some of the foreign substances, 
lead and potass. It is purified by distillation. 
17 # 



198 CHEMISTRY. 

Sulphuric acid speedily destroys the texture of animal 
and vegetable substances ; it changes all vegetable blues 
to red, with the exception of indigo. It has a strong 
attraction for water, of which Neuman asserts it will 
abstract from the atmosphere 6.25 of its own weight. 

When sulphuric acid is mixed with water, much ca- 
loric is evolved, and the specific gravity of the compound 
is greater than intermediate. The mixture of four 
pounds of acid, with one of water, will raise the ther- 
mometer to 300°. 

Sulphuric acrd decomposes alcohol and the oils; when 
assisted by heat, it decomposes most of the metallic 
oxides, and most readily those which contain the greatest 
quantity of oxygen, as the red oxide of lead, the black 
oxide of manganese. 

It oxidizes iron, zinc, and manganese in the cold. 
Assisted by heat, it oxidizes silver, mercury, copper, 
antimony, bismuth, arsenic, tin, and tellurium. At a 
boiling heat, it oxidizes lead, cobalt, nickel, and molybde- 
num. It has no action upon gold, platina, tungsten, or 
titanium. 

It unites readily with all the alkalies, and alkaline 
earths, also with alumine, and zircon ; with which, and 
most of the metallic oxides, it forms salts, which are 
called sulphates; thus sulphate of potass, formerly called 
vitriolated tartar, is a combination of the sulphuric acid 
and potass, and sulphate of soda (Glauber's salts,) is a 
combination of sulphuric acid and soda. 

SULPHUROUS ACID. 

If sulphuric acid be deprived of part of its oxygen, it 
is converted into sulphxtrous acid ; but the quantity of 
oxygen which must be abstracted to effect this change, 
or, in other words, the quantity of oxygen which is con- 
tained in sulphurous acid, has never been ascertained. 

Sulphurous acid is the result of a very slow combus- 
tion of sulphur ; whereas, in a rapid combustion, the 
sulphur combines with more oxygen, and forms sulphuric 
acid. 



TARTARIC ACID. 199 

It IS usually procured by mixing, with sulphuric acid, 
oil, grease, metals, or any other substance that has a 
stronger affinity for oxygen than sulphuric acid, and pro- 
ceeding to distillation. Sugar is one of the best substances 
which can be employed. By this means, the acid may 
be obtained in a gaseous form, in which state it is colour- 
less and invisible, like common air, exhales the odour of 
burning sulphur, and cannot be breathed without suffo- 
cation. Extreme cold converts it into a liquid. When 
combined with water, for which it has a strong attrac- 
tion, it does not entirely lose its smell like sulphuric 
acid. 

Blue vegetable colours are reddened by sulphurous 
acid, previous to their being discharged. 

This acid does not oxidize so many of the metals as 
sulphuric acid. The metals upon which it has this effect, 
appear to be only iron, zinc, and manganese. 

With the alkalies, alkaline earths, alumine, and some 
of the metallic oxides, it forms the salts called sulphites, 

TARTARIC ACID. 

A HARD substance is found adhering to the sides of 
casks in which some kinds of wine have been fermented ; 
this substance is tinged with the colour of the wine ; but, 
when it has been purified by solution, filteration, and 
crystallization, it constitutes the salt called cream of 
tartar. Cream of tartar consists of potass, united to a 
peculiar acid : this acid is tartaric acid. Cream of tar- 
tar is supertartrate of potass. 

To obtain tartaric acid, four parts of supertartrate of 
potass may be boiled in twenty parts of water, and one 
part of sulphuric acid added gradually. By continuing 
the boiling, the sulphate of potass will fall down. When 
the liquor is reduced to one-half, it is to be filtered, and 
if any more sulphate be deposited by continuing the boiU 
ing, the filtering must be repeated. When no more is 
thrown down, the liquor is to be evaporated to a syrup ; 
and thus crystals of tartaric acid equal to half the weight 



200 CHEMISTRY. 

of the tartar employed, will be obtained. These crys- 
tals readily dissolve in water, and the solution crystallizes 
by evaporation. 

The tartaric acid does not oxidize platina, gold, silver, 
lead, bismuth or tin ; and its action on antimony and 
nickel is very slight. It unites with the alkalies, and most 
of the earths. The salts formed with it are called tar- 
trates. 

The super tartrate of potass, from which this acid is 
obtained, is much used in medicine; it is cooling, and 
gently aperient : in domestic economy, it is dissolved in 
water, and, with the addition of a little sugar and a few 
slices of lemon, forms, after standing a day or two, an 
agreeable beverage, called imperial water. An infusion 
of green balm, instead of water, improves this liquor. 

Mixed with an equal weight of nitre, and thrown into 
a red hot crucible, supertartrate of potass detonates, 
and forms the white flax ; with half its weight of nitre, 
it forms the black flux ; and by simple mixture with 
nitre in various proportions, it is called raw flux. It is, 
likewise, used in dyeing, gilding, whitening pins, and other 
arts. 

TELLIRIC ACID. 

The oxide of tellurium combines with many of the 
metallic oxides, acting the part of an acid, and produ- 
cing a class of compounds which have been called tellu- 

rates. 

TUNGSTIC ACID. 

This acid has been found only in two minerals ; one 
of which, formerly called tungsten, is a tungstate of 
lime, and is very rare; and the ether, more common, is 
composed of tungstic acid, oxide of iron, and a little 
oxide of manganese. The acid is separated from the 
latter in the following way : — The wolfram, cleared from 
its silicious ganguCy and pulverized, is heated in a mat- 
trass, with five or six times its weight of muriatic acid, 
for half an hour. The oxides of iron and manganese 



TUNGSTOUS ACID, ZUMIC ACID, ZOONIC ACID, 201 

being thus dissolved, we obtain tungstic acid in the form 
of a yellow powder. After washing it repeatedly with 
water, it is then digested in an excess of liquid ammonia, 
heated, which dissolves it completely. The liquor is 
filtered and evaporated to dryness in a capsule. The 
dry residue being ignited, the ammonia flies off, and pure 
tungstic acid remains. If the whole of the wolfram has 
not been decomposed in this operation, it must be sub- 
jected to the muriatic acid again. 

It is tasteless, and does not affect vegetable colours. 
The tungstates of the alkalies and magnesia are soluble 
and crystallizable, the other earthy ones are insoluble, as 
well as those of the metallic oxides. The acid is com- 
posed of 100 parts pure metallic tungsten, and 25 or 26.4 
oxygen. 

TUNGSTOUS ACID. 

What has been thus called appears to be an oxide of 
tungsten. 

ZUMIC ACID. 

An acid produced from vegetable substances, which 
have undergone acetous fermentation. Its claim to be 
considered as a distinct compound is doubtful. (See 
JVuncic Acid.) 

ZOONIC ACID. 

In the liquid procured by distillation from animal sub- 
stances, which had been supposed only to contain car- 
bonate of ammonia and an oil, Berthollet imagined he 
had discovered a peculiar acid, to which he gave the 
name of zoonic. Thenard has demonstrated, however, 
that it is merely acetic acid combined with animal 
matter. 



202 CHEMISTRY. 



OF ALKALIES. 

Alkalies are possessed of the following properties : 

1. They are soluble in water ; 2. they have an acrid 
and urinous taste ; 3. they are incombustible ; 4. they 
change most vegetable blues to green, and the yellow to 
a brown ; 5. they form neutral salts with acids ; 6. they 
render oils miscible with water. 

Potass and soda are cMed fixed alkalies, because they 
are not volatilized except by an intense heat ; ammonia 
is called the volatile alkali, because it is dissipated or 
converted into gas at a moderate heat. 

Oxygen is a compound part of all the alkalies, and 
appears clearly in the case of two fixed alkalies, to be 
the alkalizing principle. The bases of the alkalies are 
metals. 

Table of saline products of one thousand pounds of 
ashes of the follomng vegetables : 

SALIiSrE PRODUCTS. 

Stalks of Turkey wheat or maize, 198 lbs. 

Stalks of sun-flower, - - - . 349 " 

Vine branches, 162.6 " 

Elm, 166 " 

Box, 78 " 

Sallow, 102 « 

Oak, Ill " 

Aspen, . - - - .s - - - 61 " 

Beech, 219 " 

Fir, - ... 132 " 

Fern cut in August, - - - - 117 " 

Wormwood, ------ 748 " 

Fumitory, 360 " 

Heath, ^. 115 " 



POTASS, 203 

POTASS. 

If the ashes of burnt vegetables be repeatedly lixi- 
viated, until they cease to communicate any taste to the 
water, and the water be evaporated to dryness, a 
saline residue is obtained, which in commerce is known 
by the name of potaslu It has been called the vegetable 
alkalif because it was supposed to be furnished by vege- 
tables only. 

Potash contains a number of foreign salts, and other 
impurities ; but when deprived of all these, it is called 
by chemists potass. 

Pure potass is extremely white, and so caustic, that if 
applied to the hand, the skin is instantly destroyed ; it is 
therefore in this state called caustic alkali. 

The potash of commerce is always combined with 
carbonic acid, for which it has a strong affinity, and it is 
this addition which disguises its properties more than all 
the rest, and reduces it to its usual state of what is 
called mild alkali, or by chemists carbonate of potass, 
or rather sub-carbonate of potass, as it is not saturated 
with the carbonic acid. 

If potash be dissolved in water, and mixed with an 
equal quantity of quick-lime made into a paste with the 
same fluid, the Hme having a greater affinity for the 
carbonic acid than the potass, will combine with it ; the 
potash remains in solution, and may be separated from 
the lime by Alteration. The evaporation of this solution 
should be performed in close vessels, otherwise the potass 
will abstract carbonic acid from the air. 

Potass is soluble in its weight of water. It attracts 
moisture from the gases with avidity; and, therefore, 
affords the means of drying them. It is soluble, also, in 
alcohol, which is not the case when it is in a state of 
carbonate. 

By exposure to heat, potass becomes soft ; and at the 
commencement of ignition, it melts into a transparent 
glass ; by increasing the heat, it is volatilized. 

Potass and silex, when fused together in equal quan* 



204 CHEMISTRY. 

ties, combine, and form glass. If the proportion of po- 
tass to that of silex be as three or four to one, the glass 
will be soft and soluble in water. This composition is 
called siliceous potass, or liquor of flints. 

If a solution of potass be boiled upon silex recently 
procured, it dissolves a part of it. As the solution cools, 
it assumes the appearance of a jelly, even though pre- 
viously diluted with seventeen times its weight of water. 

Potass, combined with fixed oils, forms soap. 

It combines with sulphur, both in the dry and the 
humid way, forming sulphuret of potass. When this 
sulphuret is obtained by the fusion of its component parts, 
it is of a brown colour, soluble in water, and soon attracts 
water from the atmosphere. When it has acquired 
moisture, it is then in a state to act on the air, from 
which it will abstract oxygen ; and, if inclosed with a 
quantity of it in a jar, the nitrogen will be left alone. 

Sulphuret of potass, allowed to remain moist in the 
atmosphere, is at length converted into sulphate of po- 
tass ; for the sulphur, combining with oxygen, forms sul- 
phuric acid, and the water is decomposed, giving out 
sulphuretted hydrogen gas. 

SODA. 

Soda, called also mineral, or fossil alkali, because it 
was considered as exclusively derived from the mineral 
kingdom, is nearly similar to potass in its properties. 

Soda is one of the most abundant substances, but is 
never met with naturally, except in a state of combina- 
tion. It forms common salt when combined with mu- 
riatic acid, and this acid is, therefore, called muriate of 
soda. Hence, those inexhaustible mines of salt which 
are found in England, Poland, and other countries, and 
even the ocean itself, which holds it in solution, are so 
many vast depositaries of soda. 

The French chemists have attempted to obtain muri- 
atic acid and soda, by the decomposition of sea-salt, but 
the process is too expensive for general use. The soda 



SODA. 205 

of commerce is therefore obtained from the ashes of 
marine plants, and from one of these (the salsola soda) 
it derives its name. In Scotland, this and other sea- 
weeds are collected, dried, and burned in pits dug in the 
sand, or in heaps surrounded by loose stones. Fresh 
quantities are added, as the first are consumed, and a 
hard residuum is obtained, which is of a black or bluish 
colour ; it is called kelp, and contains from 2^ to 3 per 
cent of soda. On the coasts of France and Spain the 
same kind of manufacture is carried on, and the produce 
is called barilla. The barilla of Alicant is much noted. 

Soda is obtained from kelp and barilla by lixiviation, 
Alteration, and crystallization. These processes leave it 
in the state of a carbonate, but it may be deprived of 
its carbonic acid, and rendered caustic, by lime, in the 
same manner as potass. 

Potass and soda, in a state of purity, cannot be distin- 
guished by inspection from each other. The oxalic acid 
has been used as a test to distinguish them. This acid, 
with potass, forms a very soluble salt, but with soda one 
of difficult solubility. A solution of the ore of platina 
in nitro-muriatic acid, also affords the means of dis- 
tinguishing them ; for the solution of potass will form a 
yellow precipitate, but soda gives no precipitate. 

Fourcroy suggests that soda is the most proper of the 
two fixed alkalies to be employed in medicine ; because 
animal substances always contain it, but they never con- 
tain potass. 

If potass be exposed to the atmosphere, it deliquesces, 
that is, acquires moisture ; if soda be exposed in the 
same manner, it effloresces, that is, parts with moisture, 
and is converted into a dry powder. 

Soda is preferred to potass in most manufactures, its 
affinities in general are not so strong as those of potass, 
it is therefore less corrosive. It is more fusible alone, 
and fuses silex more readily than potass, hence it is em- 
ployed in manufacture of glass. 

Carbonic acid renders soda, as well as potass, fit for 
many purposes to which, in its caustic state, it would 
18 



206 CHEMISTRY. 

not be applicable. It is in this state that these alkalies 
are employed, in medicine, and in washing linen. 

The combination of potass or soda with oil or tallow, 
forms soap; but soda forms hard soap, while potass only 
affords soft soap. Soda is therefore much more valuable, 
and generally used in the manufacture of soap, for which 
use it is rendered caustic, by quick-lime. Muriate of 
soda is added in making soap, in order to harden it. The 
brown or yellow soap contains a quantity of rosin. Black 
or green soft soap is made with the coarsest oils, and 
retains all its alkaline ley. 

The weakest acids have the power of decomposing 
soap, because they have a stronger affinity for its alkali 
than the oil. Soap is also decomposed by metallic oxides, 
earths, and neutral salts. Hence the water of springs 
is said to be hard, because soap is not soluble in it, or 
rather is not decomposed by it. Solution of soap may 
therefore be employed to show whether water holds min- 
erals in solution or not. 

AMMONIA. 

If muriate of ammonia, in powder, be mixed with 
three parts of slacked lime, and distilled, and the pro- 
duct be collected by the mercurial trough, or pneumatic 
apparatus, a gas is obtained, w^hich is transparent and 
colourless, like common air. This gas is called ammoni- 
acal gas, and is the purest state in which ammonia can 
be exhibited. 

Ammonia has a pungent, though not unpleasant smell. 
Its taste is acrid and caustic, like that of the fixed alka- 
lies, but not so strong ; nor has it the property, like them, 
of corroding animal substances. It is not respirable. 
Its specific gravity to common air is as 3 to 5. When 
exposed to a cold of 45°, it is condensed in a liquid, which 
again assumes the gaseous form, when the temperature 
is raised. 

Ammonia is rapidly absorbed by water, and the absorp- 
tion goes on till the water has acquired more than a 



AMMONIA. 207 

third of its weight of it. It therefore instantly disappears 
if water be introduced into a jar of it; some caloric is 
evolved, and the specific gravity of the water is dimin- 
ished. If ice be introduced into this gas, it melts and 
absorbs the ammonia, while at the same time its tempera- 
ture is dimished. The specific gravity of water saturated 
with ammonia, at 60° is 9054. It is the attraction of 
water for ammonia, which renders it necessary to em- 
ploy mercury in obtaining the gas. 

Water combined with ammonia, acquires its smell, 
and has a disagreeable taste ; it converts vegetable blues 
to green. It is this liquid solution of ammonia which is 
meant in speaking of the volatile alkali. When heated 
to the temperature of 130°, the ammonia separates in 
the form of gas. When its temperature is reduced to 
46°, it crystallizes ; and when suddenly cooled down to 
68°, it assumes the appearance of a thick jelly, and has 
scarcely any smell. 

Ammonia may be obtained by the dry distillation of 
bones and other animal matters ; it is from such substan- 
ces that it is obtained to supply the demand of commerce, 
and it is sold under the name of spirits of hartshorn. 
The product of the first distillation from bones, &c. is 
very impure: it is therefore improved by repeated dis- 
tillations. 

Berthollet's experiments evince that one thousand 
parts of ammonia consist of 807 parts of nitrogen, and 
193 parts of hydrogen ; Sir H. Davy having discovered 
oxygen to be the alkalizing principle in potass and soda, 
was convinced of the probability of its existing in am- 
monia. His researches confirmed this opinion, and he 
concludes the proportion of oxygen in ammonia to be at 
least 7 or 8 per cent. He also succeeded in separating 
from it a substance of a metallic nature. The ammonia 
was decomposed by galvanism in contact with mercury. 
The mercury, by combining \y\i\i about one twelve-thou- 
sandth part of this new matter, has its identity destroyed ; 
it becomes solid, and its specific gravity is reduced from 
13.5 to less than 3.0, but its colour, lustre, opacity, and 



208 CHEMISTRY. 

conducting powers remain. The difficulty of obtaining 
and operating upon this substance, has hitherto prevented 
its being sufficiently known to assign its proper place in 
the classification of bodies. 

Ammonial gas has no effect upon sulphur or phosphorus. 
Charcoal absorbs it, without altering its properties when 
cold ; but when the gas is made to pass through red-hot 
charcoal, part of the charcoal combines with it, and 
forms prussic acid. 

The two gaseous substances, ammonia and muriatic 
acid, combine rapidly, and form the solid substance called 
muriate of ammonia, which is the sal-ammoniac of com- 
merce. This is one of the most remarkable and curious 
facts : separately, ammonia and muriatic acid gas are 
two of the most pungent and volatile substances known ; 
in union they are hard, inodorous, not volatile, and possess 
but little taste. 

Muriate of ammonia was formerly supplied by Egypt, 
but it is now made in other countries (England for in- 
stance) from soot. 

Ammonia combines with oils, and forms soap ; it does 
not combine with the metals, but it changes some of 
them into oxides, and then dissolves them. Liquid am- 
monia is capable of dissolving the oxides of silver, copper, 
iron, tin, nickel, zinc, bismuth, and cobalt. Its use in 
medicine is considerable. 

PEARL-ASH. 

An impure potassa obtained by lixiviation from the 
ashes of plants. 

POTASH. 

See Potassa. 



SALTS. 209 



OF SALTS. 

The compound formed by the combination of an acid 
with an alkali, an earth, or a metallic oxide, is called a 
salt 

The term neutral salty was formerly given to ail com- 
binations of acids and alkalies, but the epithet neutral 
is now restricted to those salts in which the acid and the 
alkali completely saturate each other, and in which, 
therefore, the peculiar properties of neither can be 
detected. 

When a salt contains an excess of acid, its state is 
indicated by the addition of the word sujjcr ; and some- 
times by the term acidulous; but the latter mode of 
denoting the distinction, is yielding to the former. 

When the salt contains an excess of alkali, the pre- 
position sub is prefixed to its name, or the epithet of 
alkalinous ; but the first-mentioned addition is the most 
general and appropriate. 

The base or radical of a salt, is the alkali, the earth, 
or metallic oxide, which is combined with the acid. 

Agreeably to the piinciples which are adopted in 
forming the new nomenclature, every salt receives a 
compound name, denoting its base, and the acid which 
enters into its composition. Thus, the chemical name 
of common salt is muriate of soda, as it is a combination 
of muriatic acid and soda. Salt-petre is called nitrate 
of potass ; because it is a combination of potass and ni- 
tric acid. Glauber's salt is called sulphate of soda, as it 
is a combination of soda with sulphuric acid ; and the 
salts formed by all other acids are reduced to the same 
form of expression. 

When an acid is combined with two bases, the com- 
pound is called a triple salt, and both the bases are ex- 
pressecf : thus, we have the tartrate of potass and soda. 
A single base, combined with two acids, is denoted with 
equal precision ; thus, we have the nitro-muriate of tin. 
18^ 



210 CHEMISTRY. 

When the epithet which distinguishes the acid of a 
salt terminates in ate^ it signifies that the epithet of the 
acid itself terminates in ic ; thus, the sulphuric acid 
forms sulphates. When the epithet of the salt termi- 
nates with ite^ that of the acid itself terminates in ous ; 
thus, the sulphurous acid forms sulphites. Most of the 
salts ending in ite, extract oxygen from the atmosphere, 
and are converted into the former kind. 

The salts form a very numerous class of bodies. Four- 
croy reckons that there are 134 species; and the number 
belonging to each species is often considerable. There 
can scarcely be less than 2000 distinct salts ; but I shall 
only notice some of the most useful. 



SULPHATES, 

The sulphates are in general crystallizable, have 
some taste, but no smell ; are precipitated by solution of 
barytes, and afford sulphurets when heated red-hot with 
charcoal. They are numerous, as the sulphuric acid 
combines with all the alkalies, and nearly aJl the earths, 
and metallic oxides. » 

SULPHATE OF ALUMINE. 

Sulphate of alumine is formed by dissolving alumine 
in sulphuric acid. It has an astringent taste, is very 
soluble in water, and crystallizes in thin plates, which 
have very little consistence. It generally contains an 
excess of acid. 

I should have omitted the mention of this salt, but to 
distinguish it from the following one, to which the same 
name is apt to be given. 



SULPHATES OP ALUMINE AND SODA. 211 

SULPHATE OF ALUiMINE AND POTASS, OR 
AMMONIA, (ALUM.) 

This salt is the common alum of commerce. It has 
an austere, sweetish, astringent taste, and always reddens 
tincture of litmus. Seventy-five parts of boiling water 
dissolve 100 of alum, at the temperature of 60^ ; it is 
soluble in from 10 to 15 times its weight of cold water, 
the purest alum having the least degree of solubility. 
Its crystals are large. By exposure to the air it slightly 
effloresces. Its specific gravity is 1.7. 

According to Vanquelin, alum contains of alumina 
10.50, sulphuric acid 30.52, potass 10.40, water 48.58. 

Two kinds of alum are found in commerce, the com- 
mon and rock alum. The latter has a reddish tinge, 
from an admixture of rose-coloured earth ; it is also the 
most esteemed, and sold at the greatest price, though the 
cause of its superiority is not well known. 

The uses of alum are very extensive. In dyeing it is 
of considerable importance for fixing several vegetable 
colours. It is used in the tanning of leather, to give 
firmness to the skins, after thev have been in the lime- 
pits, and in the manufacture of candles, to give consistence 
to the tallow. Alum may also be used to advantage in 
the manufacture of wTiting-paper, to make the paper 
bear ink better. 

Alum is prepared in France by the artificial combina- 
tion of its component parts; but in Great Britain it is 
obtained from a kind of slate, called alum-slate^ which 
is plentiful on the north-east coast of Yorkshire, and near 
Glasgow ; about 100 tons of the slate only aflford 10 tons 
of alum. 

Ammonia wall contribute to the formation of alum as 
well as potass. 

SULPHATE OF SODA, (GLAUBER'S SALT.) 

The sulphate of soda has a strongly saline and bitter 
taste ; its crystals are transparent, but they effloresce 
and jfall into a white powder in the air ; it is soluble in 



212 CHEMISTRY. 

rather less than three times its weight of water at the 
temperature of 60^, and hi y^oths of its weight of boiling 
water. It is principally used in medicine as a purgative, 
under the name of Glauber's salts. According to Kirwan, 
it contains of acid 22 parts, soda 17, and water 61. 

GREExN SULPHATE OF IRON, (COPPERAS.) 

This salt is the copperas or green vitriol of commerce. 
Its crystals are of a beautiful light-green ; it has a sharp 
astringent taste, and is poisonous. It is soluble in 6 
times its weight of water at the temperature of 60°, and 
in f of its weight of boiling water. It is insoluble in 
alcohol. According to Bergman it contains of acid 39 
parts, green oxide of iron 23, and water 38. It is efflo- 
rescent. 

Green sulphate of iron is obtained by the decomposi- 
tion of pyrites or native sulphuret of iron ; and this 
decomposition is effected by simple exposure to air and 
moisture. This salt is much used in dyeing blacks and 
other intermediate colours, both wool and cotton, also, 
for the black or iron liquor of the calico printers ; hke- 
wise in preparing writing ink ; and by bookbinders for 
staining black the skins which have been tanned with 
oak bark. 

RED SULPHxlTE OF IVxON. 

If nitric acid be distilled of the green sulphate of iron, 
or the sohition of this salt be exposed to the air, the i^ed 
sulphate of iron is obtained. It is deliquescent, uncrys- 
tallizable, and soluble in alcohol. Proust observes that 
it alone forms prussian blue with prussic acid, and strikes 
a black colour with gallic acid ; and therefore, when 
these elTects are obtained by operating with the green 
sulphate, the latter salt has derived from the atmosphere, 
or some other source, the additional quantity of oxygen 
necessary to convert its iron to the state of red oxide. 



SULPHATE OF COPPER, NITRATE OF POTASS. 213 

SULPHATE OF COPPER, (BLUE VITRIOL OR 
BLUE COPPERAS.) 

The crystals of this salt, which were formerly called 
blue vitriol, are a fine deep blue. It has a strong styptic 
taste ; insoluble in four times its weight of water, and 
effloresces in the air. Its specific gravity is 2.2. It is 
generally obtained by evaporating the water of copper- 
mines. 

The sulphate of copper is employed as a caustic, to 
remove the flesh of fungous ulcers. It is dangerous to 
administer it internall)^ It is also employed in dyeing 
certain colours. 

SULPHITES. 

Sulphites have a disagreeable sulphurous taste. If 
exposed to the fire, they yield sulphur, and are converted 
into sulphates, and even by mere exposure to the atmo- 
sphere, the same change is produced. They are also 
decomposed by the nitric, muriatic, and other acids which 
do not affect sulphates. They are mostly formed ar- 
tificially. 

The principal sulphites are those of potass, soda, 
ammonia, alumine, magnesia, and barytes ; none of these 
have been applied to purposes of any importance. 

NITRATES. 

The nitrates are soluble in water, and crystallizable ; 
they deflagrate violently when heated to redness with 
charcoal, or other combustibles ; sulphuric acid disen- 
gages from them a white vapour of nitric acid. By heat 
they are decomposed, and yield at first a considerable 
quantity of oxygen gas. 

NITRATE OF POTASS, (SALTPETRE.) 

Nitrate of potass, saltpetre, or nitre, is the best known 
and most important of all the nitrates. Its taste is sharp, 



214 CHEMISTIiYo 

bitterish, and cooling. It is very brittle. Its specific 
gravity is 1.9. It is soluble in seven times its weight of 
cold water, and in rather less than its weight of boiling 
water. When mixed with one-third of its weight of 
charcoal, and thrown into a red-hot crucible, or when 
charcoal is thrown upon red-hot nitre, the combustion 
that ensues is exceedingly vivid and beautiful. The 
residuum is carbonate of potass. The combustion is still 
more violent, when phosphorus is used instead of char- 
coal. 

According to Kirwan, nitre contains acid 41.2 parts, 
potass 46.15, water 12.65. All the nitric acid employed 
in the arts, is furnished by the decomposition of this salt. 
The sulphuric acid is employed to effect the decomposi^ 
tion. Considerable quantities of nitre are also us^d in 
obtaining sulphuric acid, as it supplies the oxygen for the 
combustion of sulphur in close chambers. The manufac- 
ture of gunpowder also requires an immense quantity. 

A considerable part of the nitrate of potass consumed 
in Europe, is furnished by the East Indies, where the 
soil, being impregnated with it, yields it by lixiviation 
and evaporation. At Apulia, near Naples, also, there is 
a natural nitre-bed, in which the earth contains 40 per 
cent, of nitre. In Germany, France, and Switzerland, 
artificial nitre-beds are formed, by suffering animal and 
vegetable matters to putrefy in combination with calca- 
reous and other earths. A soil of this kind attracts the 
nitric acid from the atmosphere. Old mortar furnishes 
a very proper calcareous earth for a nitre-bed. 

NITRATE OF SODA, (CUBIC NITRE.) 

This salt was formerly called cubic nitre, from its 
crystallizing rhombs. It is somewhat more bitter than 
the nitrate of potass, rather more soluble in cold water, 
but much less soluble in hot water. It is not of any 
important use, though Proust observes, that when made 
into gunpowder, it burns longer than common nitre, and 
might therefore be economically adopted for fire-works. 



NITRATE OF AMMONIA, MURIATES. 215 

NITRATE OF AMMONIA. 

« 

Nitrate of ammonia has a sharp, acrid, and somewhat 
urinous taste ; it deliquesces in the air, and is soluble in 
about half its weight of boiling water. The only use 
made of it is to furnish nitrous oxide. 

MURIATES. 

Though the muriates are the most volatile of the salts, 
they are at the same time the least decomposable : they 
may be melted and volatilized without undergoing decom- 
position. They effervesce with sulphuric acid, and white 
acrid fumes of muriatic acid are disengaged ; when acted 
upon by nitric acid, oxymuriatic gas is disengaged. 

MURIATE OF SODA, (COMMON SALT.) 

Muriate of soda, or common salt, is too well known to 
require any description. It is the only substance to 
which the term salt was formerly applied. Besides the 
immense quantity of it held in solution by the sea-water, 
it exists in prodigious masses in the state of rock-salt. 
Its specific gravity is 2.12; and it is soluble in rather 
less than three times its weight of water. When pure, 
it is not affected by the air; but common salt is deliques- 
cent, from the magnesia and other impurities which it 
contains. 

Muriate of soda contains of acid 44 parts, soda 50, 
and of water 6. 

MURIATE OF POTASS, (SALT OF FEBRIFUGE.) 

This salt was formerly called febrifuge salt of Sylvius, 
and regenerated sea-salt It has a disagreeable, bitter 
taste; its specific gravity is 1.8; it is soluble in three 
times its weight of cold water, and twice its weight of 
boiling water. When heated, it first decrepitates, then 
melts, and at la«t is volatilized without decomposition. 
According to Kirwan, it contains of acid 36 parts, potass 
46, and water 18. 



216 CHEMISTRY. 

MURIATE OF AMMONIA, (SAL AMMONIAC.) 

Muriate of ammonia, or sal ammoniac, has an acrid, 
urinous taste, an opaque white colour, and a specific 
gravity of 1.4. It dissolves in three times its weight of 
cold water. It contains, according to Kirwan, 35 parts 
of acid, 30 of ammonia, and 35 of water. 

Muriate of ammonia is employed for brightening some 
colours in dyeing and mixing of colours ; also for pre- 
serving the surfaces of metals from oxidation in tinning ; 
in medicine it forms an excellent diaphoretic and febrifuge, 
and has been advantageously applied externally as a 
lotion for indolent tumours. 

HYPER-OXYMURIATE OF POTASS. 

If a solution of potass be saturated with oxymuriatic 
. acid gas, and then evaporated in the dark, the first 
crystals formed are those of common muriate of potass; 
when these are separated, and the solution allowed to 
cool, the crystals of the hyper-oxymuriate of potass are 
obtained. These crystals have a silvery lustre, and are 
insipid and cool to the taste. They are soluble in 17 
parts of cold water, and 2^ of boiling water. 

The hyper-oxymuriate of potass, when mixed with 
charcoal and other combustibles, and heated, detonates 
with extreme violence. It also explodes when triturated 
in a mortar, or when struck with a hammer, if a small 
quantity of it is laid upon an anvil. 

This salt consists of hyper-oxymuriatic acid 58 parts, 
potass 39, water 3. The oxygen is about equal to the 
salt in weight. It was called simply oxymuriate of potass, 
till Chenevix proved that the acid which enters into its 
composition is in the highest state of oxygenizement. 
He endeavoured to obtain this acid separately, but the 
retort containing the salt was reduced almost to powder 
by a violent explosion. The hyper-oxymuriatic acid has 
therefore never been exhibited separately. 



CARBONATES, FLUATES. 217 



CARBONATES. 

Carbonates effervesce and yield carbonic acid, when 
sulphuric or nitric acid is poured upon them ; all the 
alkaline carbonates are soluble in water, while those of 
the earths and metals are nearly insoluble, unless the 
acid be in excess. 

SUB-CARBONATE OF POTASS. 

The potass of commerce is always in the state of 
sub-carbonate ; the carbonic acid considerably weakens 
its alkaline properties, yet it will still change vegetable 
colours to green, and, combined with oils, will form an 
imperfect soap. 

SUBCARBONATE OF SODA. 

The soda of commerce is in the state of sub-carbonate ; 
but its carbonic acid deprives it of more of its alkaline 
properties than it does potass. For making glass, it is 
used in the state of a sub-carbonate, because the heat is 
exposed to drive off the carbonic acid; but to form soap, 
it must be rendered caustic, which is effected by quick- 
lime. 

CARBONATE OF LIME. 

Carbonic acid has the power of completely neutrali- 
zing the alkaline properties of lime, which it reduces to 
a state in which it is nearly tasteless. Under the name 
of chalk, marble, and limestone, we shall notice this 
compound. 

FLUATES. 

The fluates are not decomposed by heat, nor altered 

by combustibles : when sulphuric acid is poured upon 

them, they yield acrid vapours of fluoric acid, which 

corrodes glass. When reduced to powder, and heated, 

19 



218 CHEMISTRY. 

but not made red-hot, some of them become phospho- 
rescent. 

The principal fluoric salts are the fluates of lime, of 
soda, of potass, of ammonia, of barytes, of alumine, of 
silex, and of strontian ; but this acid forms fluates with 
mercury, copper, tin, iron, nickel, and several other 
metals. The whole of the fluates are factitious salts, 
except those of lime and alumine. 

FLU ATE OF LIME. 

Fluate of lime is, in England, well known under the 
name of Derbyshire spar, or Blue John. It is tasteless, 
and nearly insoluble in water. It is not altered by the 
air. Its specific gravity is 3.1. When powdered, and 
heated upon a shovel, it emits a violet-coloured light ; 
but this ceases if it be made red-hot. It is fused by a 
strong heat, and is occasionally used as a flux. It exists 
in the enamel of the human teeth. 

FLUATE OF SILEX. 

The fluoric acid gas will dissolve silex, and still re- 
tains its aerial form ; but the silex is afterwards deposited 
in crystals. 

BORATES. 

The Borates are all fusible into glass, and assist the 
fusion of other bodies, particularly metals, and metallic 
oxides ; with the metallic oxides, they form glass of dif- 
ferent colours. 

The principal salts of this class, are the sub-borate of 
soda, the borate of potass, of lime, of magnesia, and of 
alumine. 

SUB-BORATE OF SODA, (BORAX.) 

This is the only borate of any importance. It is dug 
out of wells in the kingdom of Thibet, and comes to us 
from the East Indies. It is then in a state of impurity, 
and is called tincal ; when purified, it receives the name 



ACETATES OF POTASS AND AMMONIA. 219 

of borax. It is in whitish crystals, has a styptic and 
alkaline taste, and converts vegetable blues to green. It 
is soluble in twenty times its weight of cold water, and 
six times its weight of boiling water. When melted into 
glass, it is transparent, and still soluble in water. When 
two pieces of borax are struck together in the dark, a 
flash of light is emitted. Its specific gravity is 1.740» It 
slightly effloresces in the air. 

According to Bergman, this salt consists of 39 parts 
of boracic acid, 17 of soda, and 44 of water. It is much 
used as a flux in soldering metals with the hard solders. 

ACETATES. 

The acetic salts are distinguished by their great solu- 
bility in water ; by the decomposition of the acid when 
the solution is exposed to the air ; by their being decom- 
posed by heat, and by their yielding acetic acid when 
mixed with sulphuric acid, and distilled. 

The principal acetates are those of potass, of soda, of 
ammonia, of magnesia, of barytes, of lead, and of copper. 

ACETATE OF POTASS. 
This salt has been long known, and has been distin- 
guished by almost a dozen diflferent names : of which one 
was secret foliated earth of tartar. It has a sharp 
warm taste; its crystals are white, and in the form of 
thin plates. It is soluble in alcohol, in ten times its 
weight of water, and is deliquescent. It is used in medi- 
cine. It was formerly made from distilled or even com- 
mon vinegar, but is now manufactured from pearl-ash 
and purified pyroligneous acid. 

ACETATE OF AMMONIA. 

This salt tastes like a mixture of sugar and nitre. It 
is extremely volatile ; and cannot be crj^stallized, except 
by an extremely slow evaporation. Its crystals are long 
and slender, and of a pearl-white colour. It is deliques- 
cent. Its solution has been long used medicinally under 
the name oi spirits of Mindererus. 



220 CHEMISTRY. 

ACETATE OF LEAD, (SUGAR OF LEAD.) 

This salt is formed by the solution of the white oxid^ 
of lead in the acetic acid. It has a sweet and somewhat 
astringent taste ; and is sparingly soluble in water. It 
becomes yellow by exposure to the air. Like all other 
preparations of lead, it is a strong poison, but in doses of 
a very few grains, it has been administered, with evident 
advantage, in desperate cases of internal hemorrhage. 
Its solution in water is used internally as an embrocation. 
That decomposes it. It is used considerably by the 
calico-printers in colour-making, &c. 

ACETATE OF COPPER. 

Acetate of copper has a disagreeable, coppery taste ; 
a fine deep green colour, some degree of unctuosity, is 
efflorescent, and is soluble in water and alcohol. It is 
used in dyeing : a small quantity of it does very well in 
writing-ink. It is also used in painting. In chemistry, 
it is distilled for the acetic acid it aflfords. 



TARTRATES, 

The tartrates are decomposed by a red heat. The 
earthy tartrates are less soluble than the alkaline; but 
they are all capable of combining with another base, and 
forming triple salts. 

The principal tartrates are those of potass, of potass 
and soda, of potass and ammonia, of lime, of strontian, 
and of potass and antimony. 

SUPER.TARTRATE of POTASS 

Is the cream of tartar of the stores. It has a strong, 
but not disagreeable acid taste ; is soluble in thirty times 
its weight of boiling water ; and is not altered by the ex- 
posure to the air. According to Bergman, it contains 23 
parts of potass, and 77 of acid. It is used in medicine 
as a mild aperient. It is also useful in dyeing. 



TARTRATES, PHOSPHATES. 221 

TARTRATE OF POTASS AND SODA. 

This triple salt is sold by the druggists under the 
name of Rochelle salts. It has a strongly saline bitter 
taste; is effervescent, and is soluble in about four times 
its weight of cold water. It is a mild cathartic. 

TARTRATE OF POTASS AND ANTIMONY. 

The crystals of this triple salt are of a white colour, 
and transparent. It is soluble in 60 parts of cold water. 
It is formed by precipitating the muriate of antimony 
with a hot solution of potass in distilled water. The 
precipitate being well washed and dried, nine drachms 
are to be boiled in five pounds of water, with two ounces 
and a half of super-tartrate of potass, finely powdered, 
till the powders are dissolved. The solution must then 
be strained, evaporated to a pellicle, and left to crystallize. 
In doses of from two to four grains, this is the best and 
most powerftil emetic known. 

PHOSPHATES. 

The phosphates are capable of vitrification ; are par- 
tially decomposed by sulphuric acid ; are phosphorescent 
at a high temperature ; are soluble in nitric acid, without 
effervescence ; and may be precipitated from their solu- 
tions by lime-water. 

The principal phosphates are those of potass, of soda, 
of ammonia, of lime, and of magnesia. 

PHOSPHATE OF SODA. 

The phosphate of soda has nearly the same taste as 
common salt ; it is soluble in water, and efilorescent. As 
a cathartic, it is equivalent to Glauber and Rochelle 
salts, and as its taste is much pleasanter, it has been used 
instead of those well-known medicines. It may be ad- 
ministered by dissolving in a weak broth, to which it 
10^ 



222 CHEMISTRY. 

serves as an agreeable seasoning. Dr. Pearson first pre- 
pared and introduced it. It is used in the arts as a flux 
instead of borax. 

PHOSPHATE OF SODA AI^D AMMONIA. 

This compound, which was formerly called nicrocomic 
salt, is much used as a flux in assays with the blowpipe. 
It may be obtained from human urine by evaporation. 

PHOSPHATE OF LIME. 

Phosphate of lime is white, tasteless, and insoluble in 
water. As it forms the bases of bones, it has been some- 
times called the earth of bones. It exists in milk, and 
some other animal products, also in w^heat. In Spain it 
has been found abundantly in the fossil state. 

PRUSSIATES. 

The singular afiinities of some prussiates render them 
interesting to the chemist; the simple prussiates are, 
however, little regarded, because destitute of permanen- 
cy, being decomposed merely by exposure to the air, 
unless united with a metallic oxide. The prussic acid 
does not appear capable of saturating an alkali ; and 
the weakest acid known is capable of decomposing the 
prussiates of the earths and the alkalies. 

The most important of the simple prussiates is that of 
iron ; and of triple prussiates, those of potass, soda, lime, 
and ammonia with iron. 

PRUSSIATE OF IRON. 

The prussiate of iron, or prussian blue, is, according 
to Proust, a combination of the prussic acid and red 
oxide of. iron. With the green oxide, the prussic acid 
forms a white compound, which, however, becomes 
gradually blue by exposure to the atmosphere, from the 
absorption of oxygen. It is a fine deep blue, and valua- 
ble as a pigment ; it is insoluble in water, very sparingly 



PRUSSIATES, OXIDES. 223 

soluble in acids, and not affected by exposure to the air. 
It is composed of equal parts of the acid and the oxide. 
If exposed to a strong heat, the acid is destroyed, and 
the residuum is simply oxide of iron. If the blue prus- 
siate of iron be deprived of part of its acid, by digesting 
it with alkalies, it becomes yellowish. 

PRUSSIATE OF POTASS AND IRON. 

This compound is often called prussian alkali, or prus- 
sian test. The importance of it to chemists, consists in 
its being capable of indicating whether a metal be pre- 
sent in any solution whatever, unless the metal be pla- 
tina ; and the colour of the precipitate differing with the 
metal, even the name of the metal may be known. It 
is necessary to take great care to have it perfectly pre- 
pared, otherwise it will afford false results. We have 
given Henry's directions respecting its preparations under 
the head of prussic acid. Its crystals should be well pre- 
served in a well stopped bottle filled with alcohol in 
which they are insoluble. 

OF OXIDES. 

When the oxygen united to any of the simple sub- 
stances does not give it the properties of an acid or an 
alkali, the compound is called an oxide. 

Most of the nrietals are capable of combining with dif- 
ferent proportions of oxygen, and a difference in the pro- 
portion of oxygen gives a different colour to the oxide. 

Some oxides require only an additional quantity of 
oxygen to convert them into acids; others always retain 
the character of oxides, whether possessed of the highest 
or the lowest quantity with which they will combine. 

Oxides cannot be formed except oxygen be present, 
and the oxide of any substance is heavier than the sub- 
stance itself, by a quantity exactly equal to the oxygen 
received. The young student may be reminded, that by 
the term heavier, it is not meant that the density or 



224 CHEMISTRY. 

{Specific gravity of the oxide is greater than its base, but 
the total quantity of it weighs more. 

Oxides are in general friable or pulverulent, and have 
the appearance of earths; but one of them is a fluid, 
and some of them are gases. 

OXIDES OF NITROGEN. 

NiTROGEPf combines in two proportions with oxygen, 
without producing an acid. It therefore furnishes two 
oxides, w^hich are distinguished from each other, like the 
acids, by a difference in the termination of the word 
denoting the base ; they are the nitrous oxide and nitric 
oxide. 

Nitrous oxide, — This gas, which is also knovi^n by tire 
name of gaseous oxide of nitrogen, is composed of 63 
parts of nitrogen, and 87 of oxygen by weight. It has 
a faint smell, and imparts a slight sensation of sweetness, 
when respired. It is dissolved by w^ater ; but maybe 
expelled from the water by heat unchanged. Alcohol 
absorbs more of it than water, and the essential and 
fixed oils more than alcohol ; but heat expels it from all 
these combinations. It supports combustion with more 
activity than commiOn air ; but it is, in general, necessary 
that the combustible should be kindled in the atmosphere 
or oxygen. It may be respired for a few minutes ; and 
the extraordinary effects it produces on the system, du- 
ring its respiration, and for a short time after, occasions 
it to be frequently made for this purpose, which is the 
only use, (if it may be called use,) to which it may be 
applied. To inhale it superinduces a species of intoxica- 
tion ; the mind of the person is lost for a moment to a 
right consciousness of things around him. In general, he 
laughs involuntarily and extravagantly ; exhibits the 
most frantic or preposterous gesticulations, and violent 
muscular exertion, and feels, at the same time, delight- 
fully happy. In a few moments, after having ceased to 
breathe the gas, its effects go off With nearly all per- 
sons who have breathed this gas, not the least uneasi- 
ness or languor subsequently remains ; it has even re- 



OXIDES OF NITROGEN. 225 

covered some from a state of casual debility, and restored 
them to comfortable enjoyment ; but, as there are others 
on whom less favourable effects have been produced, it 
may be a useful caution for those who have never 
breathed it, or who are not in perfect health, to take, 
in the jfirst instance, but a small dose. 

As it is important that the nitrous oxide intended to 
be inhaled should be perfectly pure, it may be proper to 
observe, that it can only be prepared with certainty by 
the decomposition of nitrate of ammonia. For this pur- 
pose, nitric acid, diluted with five or six parts of water, 
may be saturated with carbonate of ammonia, and the 
solution evaporated by a gentle heat, adding, occasion- 
ally, a little of the carbonate, to supply what is carried 
off The nitrate crystallizes in a fibrous mass, unless the 
evaporation has been carried so far as to leave it dry 
and compact. 

The nitrate should be put into a retort, and a lamp 
furnace should be employed to decompose it ; as the heat 
employed should not be raised above 450°. A pound 
of the nitrate of ammonia will yield about 5 cubical 
feet of the gas, which should be received over water, 
and afterwards allowed to stand an hour or two in con- 
tact with the water, which will absorb any ammonia 
that may have been sublimed, or any acid that may 
happen to be present. 

Nitric oxide, (sometimes called nitrous gas.) This 
gas is composed of 44 parts of nitrogen, and 56 of oxygen 
by weight. It is an invisible gas, until it comes in con- 
tact with the atmosphere, or some air which contains 
oxygen, when it assumes an orange colour. It is interest- 
ing to observe the difference between this gas, and the 
preceding, from which it only differs in containing a few 
parts more oxygen ; this gas instantly kills the animals 
which breathe it ; and even destroys plants. In general, 
also, it extinguishes light, but some substances have the 
property of decomposing it, if inflamed before being put 
into it, and of then burning with considerable splendour. 

Dr. Priestley found that water was capable of absorb- 



226 CHEMISTRY. 

ing about one tenth of nitric oxide, from which it ac- 
quired an astringent taste ; and that the water gave out 
the whole of this gas when passing to the state of 4ce. 
Oils greedily ahsorb nitric oxide, and decompose it. 
Nitric acid also absorbs it, and is converted by the 
abs^ption into nitrous acid, becoming fuming and col- 
oured at the same time. 

Nitric acid is composed of 75 parts of oxygen and 25 
parts of nitrogen ; it, therefore, bears a very near rela- 
tion to this gas, which may be converted into it, by sim- 
ply mixing it with a due proportion of oxygen. 

OXIDE OF HYDROGEN. 

Hydrogen appears to be capable of combining with 
oxygen only in one proportion, and that one forms water, 
which is the oxide of hydrogen. 

CARBONIC OXIDE. 

Carbon, combined with 60 per cent, of oxygen, forms 
carbonic oxide, which is an invisible and elastic gas, of 
rather less specific gravity than common air. This gas 
is not fit for respiration, nor will it support combustion; 
but it will itself burn, with a lambent blue flame, in 
atmospheric air. This is the only oxide of carbon which 
has been obtained. 

OXIDE OF SULPHUR. 

Sulphur, if kept for some time in fusion in an open 
vessel, absorbs about 2.4 per cent, of oxygen. This is 
the only oxide of it which is know^n ; it is of a red colour, 
and is used for taking impressions of metals. 

OXIDE OF PHOSPHORUS. 

The brown colour which phosphorus acquires by ex- 
posure to the air, is in consequence of its combination 
with oxygen, and this brown part is the oxide of phos- 
phorus. Phosphorus when mixed with its oxide, which 
it generally is when nev^^ly prepared, may be purified by 
putting it into hot water ; the oxide swims on the surface. 



METALLIC OXIDES. 227 

METALLIC OXIDES. 

Metallic oxides are exceedingly numerous ; every 
metal is capable of forming at least one oxide, and most 
metals are capable of forming several by combining with 
different proportions of oxygen. The oxygen which en- 
ters into their composition, has the singular effect of 
depriving them entirely of their lustre and cohesion, and 
reducing them to the state of earths. 

An acid has no action upon a metal, unless the oxygen 
it contains has a greater attraction for the metal put into 
it, than for the base of the acid. The acids first impart 
oxygen to metals, and then dissolve the oxide. 

The metals, in the readiness with which they imbibe 
oxygen, and the firmness with which they retain it, differ 
very considerably. From some, as manganese, it cannot 
be separated without difliculty; from others, as gold, 
silver, and platina, it is ever ready to separate, because 
of their slight aflinity for it, which constitutes their dis- 
position to resume their metallic state, and is the leading 
property of what are called noble metals. 

From the beauty and fixedness of the colours of many 
of the metallic oxides, they are used as pigments in 
painting in oil and water colours ; and as they are con- 
vertible into glass, they are admirably adapted for painting 
on enamel and porcelain. A purple colour is given by 
gold; yellow by silver: green by copper; red by iron; 
blue by cobalt ; and violet by manganese. 

As carbon and hydrogen have a stronger attraction for 
oxygen than other substances, they, or the substances 
consisting chiefly of them, are employed for reducing 
metallic oxides; the metallic oxide is mixed up with 
charcoal, oil, fat, resin, or the cheapest inflammable body 
which can be obtained, and submitted in a crucible to a 
strong heat ; the oxygen of the oxide combines with the 
hydrogen or carbon which is present, and the metal 
is obtained in its metallic state at the bottom of the 
crucible. 



228 CHEMISTRY, 

ORGANIC SUBSTANCES. 

VEGETABLES. 

Vegetables, though infinitely diversified in their ap- 
pearance and properties, are found to consist of a snnall 
number of simple substances ; carbon is the basis of them 
all, and after carbon, hydrogen and oxygen may be con- 
sidered as forming the principal part of them. Some 
vegetables contain nitrogen, others phosphorus, earths, 
and metals, but these elements are not general ; they 
belong only to particular plants, or to plants in particular 
situations. 

Although the proportions of the component parts of 
vegetables may be ascertained with considerable accu- 
racy, yet the chemist is unable to combine these com- 
ponent parts in any manner that shall produce substan- 
ces resembling the entire vegetable, or the compounded 
products which it affords. 

Plants derive a principal part of their nourishment 
from water ; their roots imbibe the water, which is 
decomposed in them, by the assistance of light and heat; 
and a part of its hydrogen becomes fixed, while a part, 
at least, of the oxygen is given out by transpiration. 
Water will hold carbon in solution, deriving it from the 
soil ; and hence the utility of dung, or putref5^ing animal 
or vegetable substances, which supply a large quantity 
of carbon, as well as hydrogen and nitrogen. Plants 
will grow, although their roots stand in such materials 
as lose no portion of their weight, and although they be 
watered with distilled water. In this case, the carbon 
of the plants is derived from the atmosphere, through the 
medium of the leaves. Perhaps, at all times, the atmo- 
sphere furnishes a part of the carbon, through the 
medium of the under-surface of the leaves; but when 
an adequate supply is derived from the roots, the leaves 
perform this office with less energy. Water impreg- 



ORGANIC SUBSTANCES. 229 

nated with carbonic acid gas, renders vegetation more 
vigorous. 

The processes of vegetation have a considerable ten- 
dency to produce equality of temperature. If the bulb 
of a thermometer be plunged into a hole in a tree, it 
indicates a higher temperature than the atmosphere in 
cold weather, and a lower temperature in hot weather. 

The most usual compound substances, furnished by 
vegetables, and which are possessed of remarkable or 
distinct characters, we shall consider separately. 

SUGAR. 

Sugar is afforded by most plants, and in some, such 
as the sugar-cane, the beet-root, the sugar-maple, the 
carrot, it is particularly abundant. It crystallizes, is 
sweet to the taste, and soluble in water and alcohol. 
Used as food, it is extremely nourishing and antiseptic. 
Treated with nitric acid, it affords oxalic acid. Lime, 
barytes, magnesia, and strontian, are soluble in the solu- 
tion of sugar. One hundred parts of sugar, contain of 
carbon 28 parts, of hydrogen 8, and of oxygen 64. 

8 

STARCH, OR FECULA. 

Starch is white, insipid, insoluble in cold water or 
alcohol, but forming with boiling water a semi-transpa- 
rent jelly. It is abundant in potatoes, wheat, barley, 
and many other plants, roots, and seeds, and may be 
separated from them by maceration in water. It dis- 
solves in cold water that contains an acid or an alkali. 

Fecula is often used as a general term for all matters 
contained in the juices of plants, and not held in solution 
by them ; sometimes we hear of amylaceous fecula ; 
this is the same w4th starch ; green fecula is also an 
expression in use, but the green colour of fecula is sel- 
dom permanent. Indigo is a blue fecula. 
20 



230 CHEMISTRY. 

ALBUMEN. 

Albumen is most abundant in those vegetables which 
fernnent and afford a vinous liquor without yeast. It is 
soluble in cold water ; but its chief characteristic is, that 
it coagulates and becomes insoluble by heat. 

GLUTEN. 

If wheaten flour be kneaded in cold running water, 
the water will carry off the mucilage and starch it con- 
tains ; and, when the water runs off colourless, a pecu- 
liar substance will remain, which is called gluten. 

Gluten composes about one-twelfth of the matter of 
w^heaten flour ; it is ductile and elastic, and of a stringy 
texture: it has some smell, but no taste. If stretched 
out, it returns to its original state. By exposure to the 
air, it becomes brown, and appears to have an oily coat- 
ing. When completely dry, it is very brittle, and resem- 
bles glue. If kept moist, it soon putrefies. It is insoluble 
in water, alcohol, or ether ; but the acids dissolve it, and 
the alkalies precipitate it. No other vegetable product 
has so near an alliance to animal matter, both in its 
appearance, which is like that of tendons, and in its 
constituent parts, into which nitrogen largely enters, and 
some ammonia. 

GELATINE. 

Gelatine, or jelly, has some resemblance to albumen, 
but differs from it in not being coagulated by heat. It 
is soluble in water, insipid, and precipitated by infusion 
of galls. It may be procured from blackberries, and 
other fruits of a similar kind. 

BITTER TRINCIPLE. 

The bitter principle of vegetables is soluble in water 
and alcohol. It is soluble in nitric acid, and precipitated 
by nitrate of silver. Its colour is yellow, or brown. Hops, 
quassia, &c. contain much of it. 



ORGANIC SUBSTANCES. 231 

NARCOTIC PRLNCIPLE. 

The narcotic principle is soluble in 400 parts of hot 
water; alcohol dissolves a twenty-fourth part of it. It 
is crystallizable, and of a white colour. It is soluble in 
all the acids without heat, and is precipitated from them 
in a white powder by alkalies. 

EXTRACTIVE MATTER. 

Extractive matter is taken up from vegetables by 
water and alcohol; and, therefore, is soluble in these 
fluids. It is insoluble in ether. It is precipitated by 
oxymuriatic acid, muriate of tin, and muriate of alumine, 
but not by gelatine. It dyes a fawn colour. In the 
roots of liquorice, it is abundant. 

TANNIN. 

Tannii^ is the name given to the peculiar principle 
which combines with the gelatine of skins, and converts 
them into leather. It is found in the gall-nut, and in 
all vegetables, or parts of vegetables, which are called 
.astringent. It has by some been deemed the astringent 
principle. It is soluble in water and alcohol, but is pre- 
cipitated by gelatine, with which it forms an insoluble 
compound, that becomes solid and elastic. 

WAX. 

Wax is in its composition very analogous to fixed 
oil. It is a vegetable product: bees are merely the 
labourers by whom it is collected; they do not alter its 
nature. If the nitric or muriatic acid be digested for 
several months upon a fixed oil, the oil passes to a sub- 
stance resembling wax. Hence wax might be inferred 
to be a fixed oil concreted by the absorption of oxygen. 
Its natural colour is yellow, but it may be whitened by 
exposing it in thin laminae to the air and sun. Alkalies 
dissolve wax, and render it miscible with water. 

In China and in North America, wax is obtained di- 
rectly from plants, and is then called vegetable-wax. 



232 CHEMISTRY. 

HONEY- 

Honey, like wax, is gathered by bees, ready formed, 
from flowers, which contain it in an organ called a nec- 
tary ; it is deleterious when gathered in districts where 
poisonous shrubs abound, of which there are many ex- 
amples in the uncultivated parts of America. Honey is 
composed of sugar, mucilage, and water. 

BIRD-LIME. 

Bird-lime is of a greenish colour, has the smell of 
linseed oil, is insipid to the taste, and is extremely viscid. 
It is perfectly soluble in ether, sparingly so in alcohol, 
and insoluble in water. By exposure to the air, it be- 
comes dry enough to be powdered, but recovers its 
viscidity by wetting it. It reddens tincture of litmus. 

The best bird-lime is supplied by the middle bark of 
the holly, which is boiled in water, left to ferment for 
several weeks, and afterwards macerated in water. 

COLOURING MATTER. 

The colouring matter of vegetables is combined with, 
1, the extractive principle ; 2, with resin ; 3, with fecula; 
4, with gum. Most of the colouring matters of vegeta- 
bles have a great affinity for the earths, particularly for 
alumine ; and for the white metallic oxides, especially 
the white oxide of tin ; also for animal fibrous matters, 
and for oxygen. On a due regard to these aflSnities, 
depends the art of dyeing. 

BerthoUet remarks, that those colouring matters which 
contain the most carbon, afford the richest and most 
lasting colours. Indigo is of this class. 

WOODY FIBRE. 

Whent thin shavings of wood are boiled in water, to 
separate the extractive matter, and afterwards in alcohol, 
to dissolve the resin, a residuum is obtained called the 
looody fibre. It constitutes the basis of the solid part of 
vegetables. It is tasteless, insoluble in water or alcohol. 



ORGANIC SUBSTANCES. 233 

but it is soluble in weak alkaline solutions, and is precip- 
itated by acids. It is also soluble in nitric acid, and 
yields oxalic acid. It is «ot liable to putrefaction by 
exposure to the air. It consists principally of carbon, 
and therefore, when burnt in close vessels, alFords much 
charcoal. 

BALSAMS. 

Balsams have a strong and fragrant smell : most of 
them are semi-fluids. When heated, the benzoic acid 
sublimes from them, which constitutes the principal dis- 
tinction between them and resins. Like resins, they are 
pbtained by incisions made in the trees affording them. 

RESINS. 

Resixs are mostly insoluble in water, but when pure, 
they are soluble in alcohol, oils, ether, alkalies, and acetic 
acid. They are sometimes brittle, somiCtimes soft and 
tough, and they all become fluid by heat. The nitric 
acid converts them into tannin. By distillation, they 
aflford volatile oil. They are all electric, and their 
electricity is negative. During combustion they aflford 
much smoke. 

MUCILAGE, OR GUM. 

The mucilage of vegetables is usually transparent, 
more ov less brittle when dry, though diflicultly pulvera- 
ble ; of an insipid, or slightly saccharine taste ; soluble 
in, or capable of combining with water in alt proportions, 
to which it giye$^ g^^^cy adhesive consistence, in propor- 
tion as its quantity is greater. It is separable, or coagu- 
lates by action of weak acids ; it is insoluble in alcohol, 
and in oil ; and capable of the acid fermentation, when 
(diluted with water. The destructive action of fire 
causes it to emit much carbonic acid, and converts it 
into coal, without exhibiting any flame. Distillation 
aflTords water, acid, a small quantity of oil, a small quan- 
tity of ammonia, and much coal. 

These are the leading properties of gums, rightly so 
20* 



234 CHEMISTRY. 

called ; but the inaccurate custom of former times ap- 
plied the term gum to all concrete vegetable juices ; so 
that in common we hear of gum copal, gum sandarach, 
and other gums, which are either pure resins, or mixture 
of resins with vegetable mucilage. 

The principal gums are, 1. the common gums, ob- 
tained from the plum, the peach, the cherry-tree, &c. 
2. Gum-arabic, which £ows naturally from the acacia, in 
Egypt, Arabia, and elsewhere. This forms a clear, 
transparent mucilage with water. 3. Gum-seneca or 
Senegal. It does not greatly differ from gum-arabic ; 
the pieces are larger and clearer, iand it seems to com- 
municate a higher degree of the adhesive quality to 
w^ater. It is much used by calico-printers, and others. 
The first sort of gums are frequently sold by this name, 
but may be known by their darker colour. 4. Gum 
adragant or tragacanth. It is obtained from a small 
plant, a species of astragalus, growing in Syria, and 
other eastern parts. It comes to us in small, white, 
contorted pieces, resembling worms. It is usually dearer 
than other gums, and forms a thicker jelly with water. 

GUM ARABIC. 

The Egyptian thorn yields the true acacia gum, or 
gum-arabic. Cairo and Alexandria were the principal 
marts for gum-arabic, till the Dutch introduced the gum 
from Senegal into Europe, about the beginning of the 
seventeenth century ; and this source now supplies the 
greater part of the vast consumption of this article. The 
tree which yields the Senegal gum growls abundantly on 
the sands along the whole of the Barbary coast, and par- 
ticularly about the river Senegal. There are several 
species, some of which yield a red astringent juice; but 
others afford only a pure, nearly colourless, insipid gunj, 
which is the great article of commerce. These trees 
are from eighteen to twenty feet high, with thorny 
branches. The gum makes its appearance about the 
middle of November, when the soil has been thoroughly 
saturated with periodical rains. The gumrity juice is 



ORGANIC SUBSTANCES. 235 

seen to ooze through the trunk and branches, and, in 
about a fortnight, it hardens into roundish drops, of a 
yellowish-white, which are. beautifully brilliant where 
they are broken off, and entirely so, when held in the 
mouth for a short time, to dissolve the outer surface. No 
clefts are made, nor any artificial means used by the 
Moors, to solicit the flowing of the gum. The lumps of 
gum-senegal are about the size of partridge-eggs, and 
the harvest continues about six v/eeks. This gum is a 
very wholesome and nutritious food; thousands of the 
Moors supporting themselves entirely upon it during the 
time of harvest. About six ounces is sufficient to support 
a man a day ; and it is besides mixed with milk, animal 
broths, and other victuals. 

Gum-arabic, or that which comes directly from Egypt 
and the Levant, only differs from the gum-senegal, in 
being of a lighter colour, and in smaller lumps; and it 
is, also, somewhat more brittle. In other respects, they 
resemble each other perfectly. 

GUxM SENEGAL. 
See Gum-arabic. 

GUM TRAGACANTH. 

We are indebted to a French traveller, by the name 
of Oliver, for the discovery, that the gum-tragacanth of 
commerce, is the produce of a species of astragalus, not 
before known. He describes it, under the name of as- 
tragalus verus. It grows in the north of Persia. Gum- 
tragacanth, or gum-dragon, (which is forced from this 
plant by the intensity of solar rays, is converted into 
irregular lumps, or vermicular pieces, bent into a variety 
of shapes, and larger or smaller proportions, according to 
the size of the wood from which it issues,) is brought 
chiefly from Turkey. The best sort is white, semi- 
transparent, dry, yet somewhat soft to the touch. 

Gum-tragacanth differs from all other gums, in giving 
a thick consistency to a much larger quantity of water, 
and in being much more difficultly soluble, or rather 



236 CHEMISTRY. 

dissolves only imperfectly. Put into water, it slowly im- 
bibes a great quantity of the liquid, swells into a large 
volume, and forms a soft, but not fluid mucilage : if more 
water be added, a fluid solution may be obtained by 
agitation ; but the liquor looks turbid and whitish, and 
on standing, the mucilage subsides, the limpid w^ater 
on the surface retaining little of the gum. Nor does the 
admixture of the preceding more soluble gums promote 
its union with the water, or render it dissoluble, or more 
durable. When gum-tragacanth and gum-arabic are 
dissolved together in water, the tragacanth separates 
from the mixture more speedily than when dissolved by 
itself. 

Tragacanth is usually preferred to other gums foF 
making up torches, and other like purposes, and is sup- 
posed likewise to be the most effectual as a medicine. 

According to Bucholtz, gum-tragacanth is composed 
of 57 parts of a matter similar to gum-arabic, and 43 of 
a peculiar substance, capable of swelling in cold water 
without dissolving, and assuming the appearance of a 
thick jelly. It is soluble in boiling water, and then forms 
a mucilaginous solution. 

BRITISH GUM. 

When starch is exposed to a temperature between 
600° and 700° it swells, and exhales a peculiar smell ; it 
becomes of a brov;n colour, and in that state is employed 
by calico-printers. It is soluble in cold water, and does 
not form a blue compound with iodine. Vanquelin fqund 
it to differ from gum in affording oxalic instead of mucous 
acid, w^hen treated with nitric acid. 

GUM COPAL. 

(The American name of all clear odoriferous gums.) 
This resinous substance is imported from Guiana, where 
it is found in the sand on the shore. It is a hard, shining, 
transparent, citron coloured, odoriferous, concrete juice 
of an American tree, but which has neither the solubility 
in water com.mon to gums, nor the solubility in alcohol 



ORGANIC SUBSTANCES. 237 

common to resins, at least in any considerable degree. 
By these properties it resembles amber. It may be dis- 
solved by digestion in linseed oil, rendered drying by 
quick-lime, with a heat very little less than sufficient to 
boil or decompose the oil. This solution, diluted with 
oil of turpentine, forms a beautiful transparent varnish, 
which, when properly applied, and slowly dried, is very 
hard and durable. This varnish is applied to snuff 
boxes, tea-boards, and other utensils. It preserves and 
gives lustre to paintings, and greatly restores the decayed 
colours of old picflPes, by filling up the cracks, and ren- 
dering the surfaces capable of reflecting light more 
uniformly. 

CAOUTCHOUC OR jGUM-ELASTIC. 

Gum-elastic or Indian rubber, possesses great elas- 
ticity ; is soluble in water and alcohol, is reduced to a 
pulp by heated spirits of turpentine, but is strictly soluble 
only in nitric ether and naphtha. The solution is ex- 
tremely adhesive, and slow in drying. 

Caoutchouc always remains soft, like leather, unless 
in a very low temperature ; it is fusible, and burns like 
resins, but with less smoke. 

Caoutchouc is prepared chiefly from the juice of the 
Siphonica elastietff^ihe manner of obtaining this juice 
is by making incisions through the bark of the.trunk of 
the lower part of the tree, from which the fluid resin 
issues in great abundance, appearing of a milky white- 
ness as it flows into the vessel placed to receive it, after 
which it inspissates into a soft, reddish, elastic resin. It 
is now manufactured into various articles of wearing 
apparel, &c, 

GUM-LAC. 

The improper name of gum-lac is given to a concrete 
brittle substance, of a dark-red colour, brought from the 
East Indies, incrustated on the twigs of the Croton Luci* 
ferum^ where it is deposited by a small insect, at present 
not scientifically known. It is found in great quantities 



238 CHEMISTRY. 

on the uncultivated mountains on both sides the Ganges ; 
and is of great use to the natives in various works of art, 
as varnishing, painting, dyeing, &c. When the resinous 
matter is broken off the v/ood into small pieces or grains, 
it is termed seed-lac^ and when melted and formed into 
flat platen, shell-lac. This substance is chiefly employed 
for making sealing-wax. A tincture of it is recommended 
as an antiscorbutic to wash the gums. 

GUM RESINS. 

Gum resins are distinguished fronJ- common resins by 
their forming milky solutions w^ith alcohol, and by their 
being infusible. Their solutions with alcohol are transpa- 
rent. Frankincense, scammony, aloes, and gum ammoniac, 
are gum resins. Both gum resins and balsams afford 
tannin w^hen treated with nitric acid. 

TAR. 

This is obtained as a secondary product in making 
charcoal of resinous woods; namely of the pine and fir 
trees. 

The general process is to mark out a circular tar 
hearth in the forest, of about 30 kitt in diameter, w^hich 
is paved with a slope towards its centre, or at least form- 
ed of a thick bed of w^ell-rammed ciay. From near the 
centre a^ trough or covered gutter is formed, which is 
frequently only a tree split, hollowed, and then joined 
together with clay, with which it is also coated to defend 
it from the fire. This trough ends in a cistern sunk in 
the ground to receive the tar as it flows from the trough. 

A pole, 15 or IS feet long, being stuck upright in the 
centre of the hearth, the billets or fagots of resinous 
wood are piled round it, in a bed about 20 feet in 
diameter. Upon this, a bed of less diameter is made, 
and so on, decreasing gradually, to form a conical pile; 
which is covered with fresh-cut turfs, having a few open- 
ings round the pile, on a level with the ground. The 
whole being left for a day or two to settle, the pole in 
the middle is withdrawn, and the pile lighted at the bot- 



ORGANIC SUBSTANCES. 239 

torn holes. When the pile is well-lighted, the holes are 
stopped, and should the fire appear by any cracks in the 
covering, fresh turfs ar^aid to the place. The third 
day, the end of the gutter is opened next the cistern, 
which had hitherto been stopped, and the tar already 
made, permitted to run out. This opening is then closed 
again, and only opened two or three times a day, during 
the remainder of the process. 

The tar thus obtained generally requires to be heated 
in large iron pots, to drive away the w^ater and pyrolig- 
neous acid that runs out along with it, and cannot be 
separated by ladling; and also to allow the sand, and 
other impurities which the tar, in this rude process, has 
acquired, to settle, and be thus separated. 

GREEN TAR. 

This is made in the same manner as common tar, 
from the wood of those trees which have done yielding 
turpentine by incision. 

Tar is used as a cheap vamish for wood-work; also, 
as a raw material to make pitch. 

PYROLIGNEOUS TAR. 

This is a secondary product, collected in distilling 
wood which is not of a resinous nature, or charcoal for 
making gunpowder. 

It may be used for the same purposes as tar ; with 
which, however, it will not unite. 

Since the use of coal gas for illumination, a secondary 
product has been obtained, which has partly superseded 
the common coal tar, which has been made in brick fur- 
naces since the year 1740. It may be used for the same 
purposes as common tar; but as some prejudices exist 
against its use, it is mostly employed for illumination. 

PITCH. 

Two methods are in general use for making pitch ; 
namely, either simply boiling the tar in large iron pots, 
or setting it on fire, and letting it burn, until, by dipping 



240 CHEMISTRY. 

a stick into it, the pitch appears to have acquired a pro- 
per consistence. 

Two barrels of the best tg|:, or 2J barrels of green 
tar, are computed to make one barrel of pitch. 

Pitch is used as a coarse varnish for ships' bottoms, 
also, to close the joints of carpenters' and coopers' works, 
to enable them to retain water. 

BROWN ROSIN. 

This is the residuum left in the still after turpentine 
has been distilled without water for its oil, and which is 
run, or ladled out of the still into casks, cut in half for 
sale. 

Its colour is more or less dark, sometimes approaching 
nearly to black, according to the degree that the distil- 
lation has been pushed. 

It is used as the base of many common varnishes and 
cements ; also, to sprinkle on the surface of metals that 
are to be joined with another metal, in order to pro- 
mote their union. It is, also, made with tallow into a 
soap. 

When melted with a little vinegar, to render it clam- 
my, it is used by violin players to rub their bows. 

YELLOW ROSIN. 

This is made by ladling out the brown rosin from the 
stills into a vessel of hot water : a violent efflorescence 
takes place, and the rosin absorbs one-eighth of its weight 
of water. 

It is used for the same purposes as brown rosin, but 
is less hard, and, therefore, less adapted for cement. Its 
light colour, however, is sometimes advantageous. 



ANIMAL SUBSTANCES. 241 



ANIMAL SUBSTANCES. 

Animal substances present us with the same constitu- 
ent principles as vegetables ; but the proportions of these 
principles are different. By destructive distillation they 
afford nnuch ammonia, which is sparingly distributed in 
the vegetable kingdom ; they also contain much nitrogen, 
of which the proportion is usually small among vegeta- 
bles ; and they are most abundant in phosphorus ; while 
of carbon and hydrogen, which are abundant in vegetables, 
they contain but little. They are also distinguished from 
vegetables by their undergoing only the putrid fermenta- 
tion, while vegetables, previous to this fermentation, 
undergo one of which the product affords alcohol, and 
another which affords vinegar. 

The distinct compound substances derived from animals, 
are very numerous ; we shall notice the most important 
of them. 

GELATINE. 

Gelatine, or jelly, is supplied by all the parts of 
animals, even bones, but is most abundant in the soft and 
white parts. It is perfectly soluble in warm water, but 
insoluble in alcohol, and has little taste or smell ; on cool- 
ing, when not difflised in too large a quantity of water, 
it has a tremulous consistence, and becomes fluid by an 
increase of heat. Gelatine is prepared for the table 
from calves' feet and the muscular part of animals. It 
is a substance strongly tending to putrefaction when com- 
bined with water, and it differs from vegetable jelly 
chiefly in this tendency ; but if it be concentrated and 
dried in a stove, it may be kept in a dry place for many 
years. In this state it forms the preparation called 
portable soup ; it is easily soluble in boiling water, and 
a very small quantity of it forms a basin of soup. 

When gelatine is obtained from the skin, cartilages, 
and refuse of animal matter, and reduced only to the 
consistence of a jellv, it is used in the arts under the 
21 



242 CHEMISTRY. 

name of size. When the gelatine is concentrated and 
dried, it forms glue. The strongest glue is afforded by 
old animals. Isinglass is a glue which consists of the 
air-bladder of the beluga ; a species of fish plentiful in 
the rivers of Russia. 

Gelatine is dissolved both by acids and alkalies. 
Tannin forms with it an insoluble compound. 

ALBUMEN. 

Aleumen, or coagulable lymph, exists in its purest 
natural state in the white of eggs, which consists almost 
entirely of it ; it is also abundant in the humours of the 
eye, and the fluid of dropsy. Its properties are similar 
to the albumen of vegetables. It is soluble in water, 
before it has been coagulated by heat, but not afterwards. 
Alkalies dissolve the coagulum. 

Albumen is coagulated by acids, and in some degree 
by alcohol. It speedily putrefies. 

FIBRIN. 

If the muscle of an animal be macerated in cold 
water, afterwards digested in alcohol, and in boiling water, 
to remove all the parts soluble by these agents, a white, 
insipid, fibrous substance remains, which is called Jibrin. 

Fibrin forms the principal part of the muscle. It is 
insoluble in water, alcohol, ether, or oils; it has neither 
taste nor smell ; it contracts when heated, and by a 
stronger heat is melted. It is soluble in acids and alka- 
lies, but not in cold liquid ammonia. Alkalies precipitate 
it from acids in flakes, which are soluble in hot water, 
and resemble gelatine. With nitric acid, it aflfords more 
nitrogen than any other substance. By destructive dis- 
tillation, it aflTords water, carbonate of ammonia, a thick, 
heavy, fetid oil, traces of acetic acid, carbonic acid, and 
carburetted hydrogen. It also contains some phosphate 
of soda and of lime. 

Fibrin exists in blood, by which it is deposited on the 
muscles. If the clotted or coagulated part of blood be 



ANIMAL SUBSTANCES. 243 

tied up in a linen cloth, and washed in water till the 
water ceases to receive either colour or taste from it, 
fibrin will remain in the linen. 

Fibrin has a very near resemblance to gluten. 

BONES. 

Bones derive solidity from the phosphate of lime, 
which forms a considerable part of them ; cartilages, 
which are bones in the first part of their formation, have 
the properties only of coagulated albumen. The gelatine 
and fat combined with bones, impart toughness and 
strength, and hence, when their quantity is diminished by 
age, the bones are easily broken. One hundred parts of 
ox-bones, according to the analysis of Fourcroy and 
Vanquelin, are composed of solid gelatine 51, phosphate 
of lime 37.7, carbonate of lime 10, phosphate of mag- 
nesia 1.3. 

The enamel of human teeth contains a greater quan- 
tity of the phosphate of lime, and is destitute of gelatine. 
The shells of animals are a species of bones ; they con- 
tain about the same quantity of carbonate of lime, that 
the bones of perfect animals contain of phosphate of 
lime. 

HORN. 

Horns, hoofs, nails, and quills, differ but little in their 
chemical characters ; they are found to consist chiefly 
of condensed albumen, with some oil, and a very small 
proportion of gelatine and phosphate of lime. 

Stag's horn and ivory are nearly the same as bone, 
and contain much gelatine. 

Hair, wool, and feathers, differ but little from each 
other in their composition ; one fourth of their weight 
consists of oil, on which their colour depends ; they afford 
besides, water, ammonia, carbon, silex, and iron. Hair 
is soluble in alkalies, with which it forms soap. 

BLOOD. 

Blood, recently drawn from an animal, appears to be 
a thin and homogeneous fluid ; but it soon separates into 



244 CHEMISTRY. 

two parts, the one a coagulated part, called the crassa- 
mentum ; the other a fluid, called the serum. 

The crassamentum is of a red colour ; it contains albu- 
men, iron, soda, and fibrin ; the fibrin constitutes its basis, 
and may be obtained separately by washing it in water. 
It has all the properties of the fibrin obtained from mus- 
cular fibre. The crassamentum has a specific gravity 
of 1.245, whereas, that of blood is only about 1.05. 

Serum is of a light greenish colour. Its taste is 
slightly saline, and it turns syrup of violets green ; this 
property it owes to the uncombined soda which it con- 
tains. It is coagulable by a temperature of 156°, and is 
then of a greyish white colour ; it, therefore, contains a 
large proportion of albumen ; it also contains gelatine, 
hydrosulphuret of ammonia, soda, muriate of soda, phos- 
phate of soda, and phosphate of lime. Acids perma- 
nently coagulate serum ; alkalies increase its fluidity ; 
alcohol coagulates it, but the coagulum is soluble in 
water. 

When the blood, after circulating through the body, 
has arrived at the lungs in its way to the heart, it has 
acquired a dark colour ; but when, in the lungs, it has 
been exposed to atmospheric air, it absorbs oxygen, with 
a minute portion of nitrogen, and parts with carbon ; 
the consequence; of this operation is its acquiring an 
increase of heat, and a fine crimson colour. 

MILK. 

Milk is usually considered as consisting of three parts ; 
the caseous, butyraceous, and serous, which, upon its 
being allowed to stand in an open vessel, spontaneously 
separate from each other. 

The butyraceous part, or cream, rises to the surface, 
and, when designed to furnish butter, it is skimmed off, 
and, being -put into a vessel in which it can be rapidly 
agitated, the butter separates from it. Butter, when 
fluid, is transparent ; but it becomes opaque, as it cools 
and hardens. The butter of cows' milk becomes harder 
than that of any other animal. 



ANIMAL SUBSTANCES. 245 

The caseous, or cheesy part of milk is obtained by co- 
agulating milk with an acid. For this purpose, in pre- 
paring cheese from cows' milk, rennet is used which is 
the stomach of a calf in which milk has soured. The 
coagulum is separated from the fluid part, to make 
cheese. 

After the whole of the matter which is capable of co- 
agulating is separated from milk, the serous, or watery 
part only remains: but rennet, from its sHght acidity, 
does not make a complete separation. The fluid, there- 
fore, remaining after rennet has been used, still contains 
saccharine particles and curd, and, under the name of 
whey, is used as a wholesome beverage. The serum ob- 
tained by the spontaneous decomposition of milk is acidu- 
lous, and totally devoid of nourishment. 

If sweet whey be evaporated to the consistence of 
honey, and afterwards dried in the sun, a solid substance 
is obtained, which is called sugar of milk. If the sugar 
of milk thus prepared be dissolved in water, it may be 
clarified by whites of eggs, and will afford white crystals, 
after being evaporated to the consistence of a syrup. 
Sugar of milk is soluble in three or four parts of water: 
its taste is slightly sweet; and it yields, by distillation, 
nearly the same products as other sugar. 

Milk is capable of undergoing the vinous fermentation, 
and, consequently, of affording a spiritous liquor. Marco 
Polo, who wrote in the thirteenth century, asserted, that 
liquor prepared from mares' milk, by the Tartars, 
might be taken for white wine. If milk be deprived 
of its cream, it will not afford a spiritous fluid. 

Thenard gives the following as the component parts 
of milk; 1, water; 2, acetous acid ; 3, caseous; 4, buty- 
raceous; 5, saccharine; and 6, by extractive matter; 
7, 8, muriate of soda, and potass; 9, Sulphate of potass; 
10, 11, phosphates of lime and magnesia. The acid here 
called the acetous, is now found to have different pro- 
perties, and is called the lactic acid. (See Lactic acid,) 
The milk of different animals in its composition — asses' 
mares^ and womens' milk — are the most saline and 
21* 



246 CHEMISTRY. 

serous ; cows', goats', and sheep's, contain the most of tlie 
caseous and butyraceous parts. 

CARTILAGE. 

A WHITE, elastic, glistening substance, growing to the 
bones, and commonly called gristle. Cartilages are di- 
vided, by anatomists, into obdiicent, which cover the 
moveable articulations of bones; nnd inter articular^\\h\ch 
are situated between the articulations and uniting car- 
tilages, which unite one bone with another. Their use 
is, to facilitate the motions of bones, or to connect them 
together. 

The chemical analysis of cartilage affords one-third 
the weight of the bones, when the calcareous salts ^re 
removed by digestion in dilute muriatic acid. It resem- 
bles coagulated albumen. Nitric acid converts it into 
gelatine. With alkalies, it forms an animal soap. Carti- 
lage is the primitive paste into which the calcareous salts 
are deposited in the young animal, In the disease, rick- 
ets, the early matter is withdrawn by morbid absorption, 
and the bones return into the state nearly of flexible 
cartilage. Hence arise the distortions characteristic of 
this disease. 

ANIMAL GLUTEN. 

This substance constitutes the basis of the fibres of 
all solid parts. It resembles in its properties, the gluten 
of vegetables. 

GLUE. 

An inspissated jelly, made from the parings of hides, 
and other offals, by boiling them in water, straining 
through a wicker basket, suffering the impurities to sub- 
side, and then bqiling it a second time. The articles 
should first be digested in lime-water, to cleanse them 
from grease and dirt, then steeped in water, stirring them 
well from time to time ; and, lastly, laid in a heap, to 
have the water pressed out, before they are put into the 
toiler. Some recommend that the water should be kept 



BlTU31INOUft SUBSTANCES. 247 

as nearly as possible to a boiling heat, without suffering 
it to enter into ebullition. In this state, it is poured into 
flat frames or moulds, then cut into square pieces when 
congealed, and, afterwards, dried in a coarse net. It is 
said to improve by age ; and that glue is reckoned the 
best, which swells considerably, without dissolving, by 
three or four days' infusion in cold water, and recovers 
its former dimensions and properties by drying. Shreds, 
or parings of vellum, parchment, or white leather, make 
a clear, and almost colourless glue. (See Mechanical 
Exercises.) 



BITUMINOUS SUBSTANCES. 

ASPHALTUM. 

AsPHALTUM is a smooth, hard, brittle, black or brown 
substance, which breaks with a polish, melts easily when 
heated, and when pure burns without leaving any ashes. 
It is found in a soft or liquid state on the surface of the 
Dead Sea, but by age grows dry and hard. The same 
kind of bitumen is likewise found in the earth in other 
parts of the world ; in China, America, particularly in 
the Island of Trinidad; and in some parts of Europe, as 
the Carpathian hills, France, Neufchatel, &c. 

According to Neumann, the asphaltum of the shops is 
a very different compound from the native bitumen ; and 
varies, of course, in its properties, according to the nature 
of the ingredients made use of in forming it. On this 
account, and probably from other reasons, the use of 
asphaltum, as an article of the materia medica, is totally 
laid aside. 

The Egyptians used asphaltum in embalming, under 
the name of mumia mineralis, for which it is well 
adapted. It was used for mortar at Babylon. 

BITUMENS. 

This term includes a considerable range of inflam- 
mable mineral substances, burning with flame in the open 



248 CHEMISTRY. 

air. They are of different consistency, fronn a thin fluid 
to a solid ; but the solids are for the most part liquefiable 
at a moderate heat. The fluid are, 

1. Naphtha, a fine, white, thin, fragrant, colourless oil, 
which issues out of white, yellow, or black clays in 
Persia and Media. This is highly inflammable, and is 
decomposed by distillation. It dissolves resins, and the 
essential oils of thyme and lavender ; but is not itself 
soluble either in alcohol or ether. It is the lightest of 
all the dense fluids, its specific gravity being 0.708. 

2. Petroleum, which is from a yellow, reddish, brown, 
greenish, or blackish oil, found dropping from rocks, or 
issuing from the earth, in the duchy of Modena, and in 
various other parts of Europe, and Asia. This, like- 
wise, is insoluble in alcohol, and seems to consist of 
naphtha, thickened by exposure to the atmosphere. It 
contains a portion of the succinic acid. 

3. Barbadoes tar, which is a viscid, brown, or black 
inflammable substance, insoluble in alcohol, and contain- 
ing the succinic acid. This appears to be the mineral 
oil in its third state of alteration. 

The solid are, 1. Asphaltum, mineral pitch, of which 
there are three varieties : the cohesive ; the semi-com- 
pact, maltha; the compact, or asphaltum. These are 
smooth, more or less hard or brittle, inflammable sub- 
stances, which melt easily, and burn without leaving any 
or but Httle ashes if they be pure. They are slightly 
and partially acted on by alcohol and ether. (See 
Asphaltum,) 

2. Mineral tallow, which is a white substance of the 
consistence of tallow, and as greasy, although more 
brittle. It was found in the sea on the coast of Finland, 
in the year 1736; and is also met with in some rocky 
parts of Persia. It is near one-fifth lighter than tallow ; 
burns with a blue flame and a smell of grease, leaving a 
black viscid matter behind, which is more diflacultly 
consumed. 

3. Elastic bitumen, or mineral caoutchouc, of which 
there are two varieties. Besides these, there are other 



BITUMINOUS SUBSTANCES, 249 

bituminous substances, as jet and amber, which approach 
the harder bitumens in their nature; and all the varieties 
of pit-coal, and the bifuminbus schistres, or shale, which 
contain more or less of bitumen in their composition. 

AMBER. 

A BEAUTIFUL bitumitious substance, which takes a good 
polish, and after a slight rubbing, becomes so electric, as 
to attract straws and small bodies. Amber is a hard, 
brittle, tasteless substance, sometimes perfectly transpa- 
rent, but mostly semi-transparent or opaque, and of a 
glossy surface ; it is found of all colours, but chiefly 
yellow or orange, and often contains leaves or insects ; 
its specific gravity is from 1.065 to 1.100; its fracture is 
even, smooth, and glossy ; it is capable of a fine polish, 
and becomes electric by friction ; when rubbed or heated, 
it gives a peculiar agreeable smell, particularly when it 
melts, that is at 550^ of Fahrenheit, but then it loses its 
transparency ; projected on burning coals, it burns with 
a whitish flame, and a whitish yellow smoke, but gives 
very little soot and leaves brownish ashes ; it is insoluble 
in water and alcohol, though the latter, w-hen highly 
rectified, extracts a reddish colour from it ; but is soluble 
in the sulphuric acid, which then acquires a reddish 
purple colour, and is precipitable from it by v/ater. No 
other acid dissolves it, nor is it soluble in essential or 
expressed oils, without some decomposition and long di- 
gestion ; but pure alkali dissolves it. By distillation it 
aflords a small quantity of water, with a little acetous 
acid, an oil, and a peculiar acid. 

Amber is met with plentifully in regular mines in some 
parts of Prussia. The upper surface is composed of 
sand, under which is a stratum of loam, and under this 
a bed of wood, partly entire, but chiefly mouldered or 
changed into a bituminous substance. Under the wood 
is a stratum of sulphuric or rather aluminous mineral, 
in which the amber is found. Strong sulphuric exhala- 
tions are often perceived in the pits. Detached pieces 
are also found occasionally on the sea coast in various 



250 CHEMISTRY. 

countries. It has been found in gravel beds near London. 
In the Royal Cabinet at BerHn there is a mass of ISlbs, 
weight, supposed to be the largest ever found. Jussieu 
asserts, that the delicate insects in amber, which prove 
the tranquillity of its formation, are not European. 
Hany has pointed out the following distinction between 
mellite and copal, the bodies which most closely resem- 
ble amber. Mellite is infusible by heat. A bit of copal 
heated at the end of a knife takes fire, melting into 
drops, which flatten as they fall ; whereas amber burns 
with spitting and frothing : and when its liquified parti- 
cles drop, they rebound from the plane which receives 
them. The origin of amber is at present involved in 
perfect obscurity, though the rapid progress of vegetable 
chemistry promises soon to throw light on it. Various 
frauds are practised with this substance. Neumann 
states as the common practice of workmen, the two 
following : The one consists in surrounding the amber 
with sand in an iron pot, and cementing it with a gradual 
fire for forty hours, some small pieces placed near the 
sides of the vessel being occasionally taken out for judging 
of the effect of the operation : the second method, which 
he says is that most generally practised, is by digesting 
and boiling the amber about twenty hours with rapeseed 
oil, by which it is rendered both clear and hard. 

Werner has divided it into two sub-species, the white 
and the yellow ; but there is little advantage in the dis- 
tinction. Its ultimate constituents are the same with 
those of vegetable bodies in general ; viz. carbon, hydro- 
gen, and oxygen. 

In the second volume of the Edinburgh Philosophical 
Journal, Dr. Brewster has given an account of some 
optical properties of amber, from which he considers it 
established beyond a doubt, that amber is an indurated 
vegetable juice ; and that the traces of a regular struc- 
ture, indicated by its action upon polarized light, are 
not the effect of the ordinary laws of crystallization by 
which mellite has been formed, but are produced by the 
same causes which influence the mechanical condition of 



' OF CRYSTALLIZATION. 251 

gum-arabic, and other gums, which are known to be 
formed by the successive deposition and induration of 
vegetable fluids. 



OF CRYSTALLIZATION. 

Crystals are aggregations of the particles of bodies, 
which have been spontaneously disposed in a regular 
form; and crystallization denotes the act of their forma- 
tion. According to the strict meaning of the word, a 
crystal should be transparent, as well as symmetrical in 
its form ; but it is now extended to opaque substances, and 
regularity of form is its leading characteristic. 

Crystallization is of two kinds, the dry and the humid ; 
dry crystallization refers to metals and other substances 
which cannot combine with water; the humid crystalliza- 
tion refers to fluids and gases holding solids in solution ; 
and which never affords crystals but what contain more 
or less water. 

The water combined with a crystal is called its water 
of crystallization. No crystals are transparent unless 
they contain water. The water, in thus combining with 
bodies, loses its caloric of fluidity. 

The same substance, under the same circumstances, 
always affords crystals of the same figure ; but except- 
ing the circumstances which modify the natural process 
of crystallization, all the differences observed in the forms 
of crystals, are attributable to differences in the forms 
of the integral particles of the crystals. 

Crystallization cannot take place unless the particles 
of bodies be at Hberty to arrange themselves according to 
their peculiar attractions. Hence it is necessary, either 
that they be in a state of solution, or suspended in a 
fluid, in a state of extremely minute division, or in fusion. 
It has not been decisively proved that mere suspension 
will produce such a regular arrangement of particles as 
can be called crystallization ; but admitting this to be 



252 CHEMISTRY. 

possible, the division of the particles which form the 
crystals must be carried so far as scarcely to differ from 
solution, and the same explanation will apply as to solu- 
tion. 

Suppose we have a saturated solution of common salt 
in water ; the particles of the salt are so completely dis- 
persed through the water, and probably so far removed 
from each other, that the particles of the water exert a 
stronger attraction on them than they exert on each 
other : the solution, therefore, remains perfect ; but let 
some of the water be evaporated ; it is now evident that 
as the same quantity of salt is contained in a less compass, 
the particles of the salt must have approximated each 
other, and are within the sphere of each other's attrac- 
tion : they, therefore, aggregate and form crystals, until 
the solution is of the same intensity as at first. If the 
evaporation be resumed, more crystals are formed in the 
same manner, until at last, by the evaporation of the 
whole of the water, the crystals are obtained dry. 

The crystallization of a metal is not essentially differ- 
ent from an aqueous crystallization. The metal may be 
regarded as held in solution by caloric ; and, as the ca- 
loric of fluidity is withdrawn by the cooling of the metal, 
the case is correspondent to that of the reduction of the 
quantity of water in the aqueous solution, and the parti- 
cles will arrange themselves according to their form. 
It must be obvious, that if the particles of the metal, 
or of the solid in solution, consist of cubes, they will ag- 
gregate in forms of one description ; and, if they are 
tetrahedrons, they must place themselves upon each 
other in another. 

A fluid which has furnished all, or the greater part of 
the crystals that can be obtained from it, is called mother- 
water. 

In general, fluids at a boiling-heat hold in solution a 
much larger portion of any matter than when cold, be- 
cause caloric has a powerful effect in lessening the 
attraction of aggregation, and preventing particles which 
are very near from combining. Common salt is, how- 



CRYSTALLIZATION. 253 

ever, an instance of a common salt which is nearly as 
soluble in cold, as in hot water : but it appears to be a 
general law, that salts of this kind require but a small 
quantity of the water of crystallization. 

Salts which acquire moisture from the atmosphere, so 
as to become fluid or pulpy, are said to be deliquescent : 
when they lose their crystalline form in the air, and yet 
remain dry and powdery, it is because their water of 
crystallization has been abstracted ; and they are said to 
be efflorescent. 

A salt is deliquescent, when it has a greater attrac- 
tion for water than the air; as it will, in that case, take 
water from the air : a salt is efilorescent, when it has 
a less attraction for water than the air ; for the air will 
then abstract water from it. When the salt has the 
same attraction for water with the air, it will suffer no 
change. 

The slower the crystallization, the larger, the harder, 
the more regular and transparent, the crystals which 
are formed. A rapid evaporation of a solution, there- 
fore, produces imperfect crystals, the particles not having 
time to assume the exact arrangement to which they are 
naturally disposed. 

Crystallization is promoted when the solution is fur- 
nished with some point at which it may commence. 

In a saturated solution which exhibits no signs of crys- 
tallization, crystals will soon be observed, if a thread be 
stretched through it. But if, instead of any foreign mat- 
ter, a crystal of substance i^ solution be introduced, the 
crystallization is still further promoted. Upon this fact, 
Le Blanc founded a method of obtaining very large and 
perfect crystals. He selected the largest and most per- 
fect crystals of salt recently formed, and put them into a 
saturated solution of the same salt. As the side of a 
crystal in contact with the vessel receives no increase, 
they were turned daily. After a certain time, the largest 
and most regular crystals thus obtained were employed 
as the nucleus of still larger crystals, by a repetition of 
the process. 
22 



254 CHEMISTRY. *^ 

Kirwan observed, that if two salts be held in solution 
by the same fluid, a crystal of either will cause that salt 
to crystallize which is of the same kind as itself. 

Crystallization goes on but very slowly in closed ves- 
sels; and, in most instances, wholly stops: but Dr. Hig- 
gins inferred, from his experiments, that the atmosphere 
only facilitates the process in consequence of its pressure ; 
and, therefore, a sufficient column of mercury, or any 
other pressure, has the same effect. Perhaps the ex- 
periment has not been tried in a proper manner: the 
pressure upon the surface of a fluid, in a closed vessel 
containing air, is not less than when that vessel is un- 
covered. 

The action of light has the effect of impeding and dis- 
turbing crystallization : and crystals are, therefore, 
larger, and more regular, when formed in the dark. 

A very singular discovery was accidentally made by 
Hany, respecting the elementary forms of crystals. 
Happening to take up a hexangular prism of calcareous 
spar, which had been detached from a group of the 
same kind, he observed that a part of the crystal was 
wanting, and yet that it presented a smooth surface. 
Attempting to detach a segment from the contiguous 
edge, he could not succeed; but the ore next it was 
easily divided. Proceeding thus to divide the crystals 
mechanically, in such a way that the separation was 
easy, and left smooth surfaces, and which did not hap- 
pen unless in directions parallel to the first fracture, he 
found that the crystal changed its form as parts of it 
were separated, until at length it acquired a form that 
remained mathematically the ^ame after any subsequent 
sections. On trying the experiment, he found that other 
crystals of the same spar were reducible to the same 
unalterable form ; and that crystals of other bodies 
were also reducible to fixed forms, of one kind or an- 
other. These fixed forms, therefore, he denominates 
the primitive forms of the crystals ; and tlie other 
forms vi^hich crystals assume, he calls their secondary 
forms. 



COMBUSTION. 255 

The primitive form of a fluate of iron, Hany found 
to be an octahedron ; of sulphate of barytes, a prism, 
with rhomboidal bases; of corundam, a rhomboid, 
somewhat acute; of beryl, an hexahedral prism; of 
blend, a dodecahedron, with rhomboidal sides. 

Pursuing the path which these discoveries pointed out, 
with a rare combination of industry and ingenuity, he 
succeeded in delineating a system of crystalography, 
which, though yet in its infancy, bears the strongest indi- 
cations of remaining consistent with the phenomena of 
nature, and, therefore, of obtaining a permanent recep- 
tion in science. 

OF COMBUSTION. 

Combustion is the union of a body with oxygen accom- 
panied by the evolution of light and heat ; and, there- 
fore, every body which is capable of forming this union, 
is called a combustible. 

Oxygen is retained in the gaseous state by the large 
quantity of caloric with which it is combined, and for 
which it has a strong attraction ; but if any substance 
be presented to the oxygen gas, that has a stronger 
attraction for oxygen than oxygen has for caloric, the 
consequence is, that the oxygen gas is decomposed, its 
particles unite with the substance thus presented to it, 
and a great part of the caloric being then left in an 
uncombined state, recoveis the properties which are 
peculiar to it in that state, that is, it assumes the appear- 
ance of fire. The heat thus produced is the more 
intense, the greater the quantity of caloric which is 
liberated in a given compass and time ; and these cir- 
cumstances are dependent upon the strength of the 
affinity between oxygen and the substance which sepa- 
rates it from caloric, and the quantity of caloric required 
to saturate the product of combustion. 

At the ordinary temperature of the atmosphere, bodies 
have either no affinity for oxygen, or usually a very weak 
one ; hence they suffer no change, or the change which 



256 CHEMISTRY. 

does take place is so slow, that though a combustion in 
effect, it is not called by that name, because neither light 
nor heat are perceptible to the senses. 

When the temperature of a combustible is raised, its 
affinity for oxygen is increased ; and when it is raised to 
a certain point, which varies according to the nature of 
the substance, the affinity becomes very strong, the com- 
bustion is consequently rapid and brilliant, taking, accord- 
ing to the phenomena it presents, the name of ignition, 
inflammation, decrepitation, detonation, or fulmination. 

Light appears to form a component part of all com- 
bustible bodies, and to enter, as well as caloric, into the 
composition of oxygen itself. Hence, when oxygen by 
combustion enters into a new combination, part at least 
of the light held both by it and the combustible, is dis- 
engaged and flies off, as well as the caloric. In general 
it appears evident, that the light is furnished by the com- 
bustible, because the light furnished by different com- 
bustibles is of different colours, and the quantity of it is 
by no means proportionate to the quantity of oxygen 
consumed. For example, hydrogen in combustion com- 
bines with a greater quantity of oxygen than any other 
body ; but the light afforded is inconsiderable. 

Although the light furnished by combustion is not pro- 
portionable to the quantity of oxygen which enters into 
combination, and therefore is evidently not wholly fur- 
nished by the oxygen, yet the case is the reverse with 
the caloric evolved. The combustion of those bodies 
which combine with the greatest quantity of oxygen, 
always furnishes the greatest quantity of caloric, and 
therefore the combustion of hydrogen furnishes the most 
intense heat that can be produced, until some other sub- 
stance shall be found which combines with a greater 
quantity of oxygen. 

Another proof that the chief part of the calorie ex- 
tricated during combustion is furnished by the oxygen, 
which when it ceases to be a gas, has no longer occasion 
for it, is, that when the oxygen is in combination with a 
fluid, a combustible substance, for example, a metal, will 



OF COMBUSTION. 257 

abstract it from the fluid, but the usual phenomena of 
combustion do not appear, although the combination with 
oxygen is so rapid, that if the same quantity of oxygen 
had been derived from a gas, in the same time, these 
phenomena would have been exhibited with considerable 
splendour. 

Bodies which have been once thoroughly burnt, which 
is only another w^ay of expressing that they are saturated 
with oxygen, are incapable of undergoing combustion 
again, until some part or all of their oxygen is abstracted. 
To deprive them of their oxygen is virtually to unburn 
them ; and when no part of a combustible has been dis- 
sipated, but only changed by Ihe new combination, the 
abstraction of the oxygen absorbed restores its pristine 
properties. This is the case with metals, which acquire 
by combustion a weight equal to the oxygen combined 
with them, and of course lose that acquired part of their 
weight when the oxygen which constitutes it is with- 
drawn ; but vegetables and other combustible matters 
containing many volatile parts, when burnt in the open 
air, have these parts dissipated, and therefore the pro- 
ducts they afford after combustion, weigh considerably 
less than the vegetables themselves, as they only consist 
of those parts which cannot be converted into gas. 

We have stated that many substances, by their union 
with oxygen in combustion, are converted into acids ; 
when this happens, the combustible is said to be oxygen- 
ized ; when the product of combustion is not an acid, it 
is called an oxide, and the combustible is said to be 
oxidized. 

The experiments which have proved the alkalies and 
earths to be metallic oxides, have tended materially to 
establish the conclusion, that all substances are either 
combustible, or combined with oxygen to the point of 
saturation ; and if this be maintained, oxygen must, like 
caloric, have an afiinity for every substance existing. 
22* 



ELECTRICITY. 

A PROPERTY which certain bodies possess when rubbed, 
heated, or otherwise excited, whereby they attract re- 
mote bodies, and frequently emit sparks, or streams of 
light 

Abstract of Electricity. 

1. Electricity is supposed to be a fluid, which repels 
its own particles, but attracts all other matter. 

2. That portion of electricity which every body is sup- 
posed to contain, is called its natural share, 

3. When a body is possessed of either more or less than 
its natural share, it is said to be electrified or charged. 

4. If it possesses more than its natural share, it is said 
to be positively electrified : if it contains less than its 
natural share, it is said to be negatively electrified. 

5. Bodies through which the electric fluid passes free- 
ly, are called conductors^ or non-electrics. Those bodies 
which oppose the passage of electricity, are called non- 
conductors, or electrics. 

6. Glass, and some other bodies, which are non-con- 
ductors at common temperature, become conductors, 
when very hot. 

7. The equilibrium of the electric fluid is disturbed by 
the friction of bodies against each other ; and electricity 
is then said to be produced, or excited. 

8. Electricity is excited in the greatest quantity by 
the friction of conductors and non-conductors against 
each other. 

9. The same substance, excited by a different rubber, 
will alternately be electrified positively and negatively. 

10. Two bodies, both positively, or both negatively, 
electrified, repel each other; whereas, if one body be 
positive, and the other negative, they will attract each 
other. 

11. Upon this principle are constructed electrometers, 
or instruments for ascertaining whether bodies are elec- 
trified or not. 

(258) 



ELECTRICITY. 259 

12. If a body, containing only its natural share of 
electricity, be presented sufficiently near to a body elec- 
trified positively or negatively, a quantity of electricity 
will force itself through the air, fronn the latter to the 
fornner, appearing in the form of a spark. 

13. When two bodies approach each other sufficiently 
near, one of which is electrified positively^ and the other 
negativelyy the superabundant electricity rushes vio- 
lently from one to the other, to restore the equilibrium 
between them. This efifect also takes place, if the two 
bodies be connected by a conducting substance. 

14. If an animal be placed so as to form part of this 
circuit, the electricity, in passing through it, produces 
a sudden eflfect upon it, which is called the electric 
shock* 

15. The motion of electricity, in passing from a posi- 
tive to a negative body, is so rapid, that it appears to be 
instantaneous. 

16. When any part of a piece of glass or other elec- 
tric is presented to a body electrified positively or nega- 
tively, that part becomes possessed of the contrary elec- 
tricity to the side of the body it is presented to ; and the 
other side of the glass is possessed of the same kind of 
electricity as the other body, 

17. The electricity communicated to glass and other 
perfect electrics, does not spread, but is confined to the 
part where it is communicated, on account of the non- 
conducting quality of the glass. 

18. To effect the communication, and to enable it to 
be applied to the whole surface, the glass is covered on 
both sides with tin-foil, or some other conductor, in which 
case the glass is said to be coated. 

19. If a communication by means of a conductor, be 
made between the two sides of a glass thus coated and 
charged with electricity, a discharge takes place, by 
which the two sides recover their natural state. 

20. The coated glass may either be flat or any other 
form ; but cylindrical jars are found to be the most con- 
venient form. The Leyden phial is nothing more than 
a glass of this description. 



260 ELECTRICITY. 

21. When several jars or phials are connected together 
so as to be charged and discharged simultaneously, they 
constitute an electrical battery^ 

22. Electricity is capable of producing the most power- 
ful effects, melting the metals, and firing all the inflam- 
mable substances. A strong shock sent through metallic 
oxides, frequently reduces them to a metallic state. 

23. The machines by which electricity is artificially 
accumulated, for the purpose of charging jars or bat- 
teries, are constructed with either a cylinder ov plate of 
glass, which is whirled round in contact with a body 
called a rubber, and the electricity is taken off as it is 
produced, by a non-electric called the prime conductor. 

24. Cylinder machines are the most easily constructed ; 
but plate machines are the most compact and elegant. 

25. Several bodies become transparent during the pas- 
sage of electricity through them ; a circumstance which 
has given rise to the conjecture that electricity may be 
the cause of all transparency. 

26. Metallic points attract the electricity from bodies, 
and discharge them silently. This property has ren- 
dered them useful in defending from lightning. 

27* When electricity enters a point, it appears in the 
form of a star ; when it issues from a point, it puts on 
the appearance of a brush or pencil. 

28. Machines may be put in motion by the electric 
fluid which issues from a point 

29. The shock of an electric battery will communicate 
magnetisrii to steel b^ars lying in or near the magnetic 
meridian ; and a magnetic bar may have its poles re- 
versed, or its magnetic properties destroyed, by impart- 
ing the shock while it is in different positions. 

30. Electricity is evolved in heating and cooling of 
varioys bodies ; also in tjie evaporjation and condensation 
of vapours. 

31. Vapour requires, for its natural share, a greater 
quantity of electricity than waiter, from which it was 
produced, 

32. When a quantity of vapour is, ip any degree, con- 



GALVANISM. 261 

densed, it has, therefore, electricity to give out; that is, 
in the positive state. When a quantity of vapour is fur- 
ther expanded, it requires, for its natural share, more 
electricity than before ; that is, in the negative state. 

33. By the ascent of vapour, immense quantities of 
electricity are carried from its reservoir, the earth ; and, 
by the unceasing alternations of rarefaction and conden- 
sation, the atmosphere is always more or less in an elec- 
trical state. 

34. Lightning is a vast accumulation of electricity. 

35. Thunder is the noise produced by the solid parti- 
cles of air rushing together, after having been separated 
by lightning ; the rapidity of the motion of which is such 
as to produce a vacuum as it proceeds. 

36. In the eruptions from volcanoes, lightning is almost 
always present ; and earthquakes are generally accom- 
panied by a disordered state of the atmosphere ; often, 
with great thunder-storms. Hence, electricity is sup- 
posed to be intimately connected with these phenomena. 

37. In the healing art, electricity appears capable of 
producing, in many cases, the most excellent effects. In 
applying it, the general rule is to begin gently, and to 
continue the application, at periodical intervals, for a 
considerable time. 



GALYAXISM. 

Galvanism is a species of electricity which is produced 
by a peculiar action of metallic and other electrical con- 
ductors on each other. 

Abstract of Galvanism. 

1. Galvanism appears only to be a method of exciting 
electricity. The first eflScient observation of its effects 
originated with Galvani, from whom it deriv^es its name ; 
but it was Volta w^ho first rendered it interesting, by dis- 
covering the method of accumulating it. 

2. Galvanic electricity is produced by the chemical 



262 MAGNETISM. 

action of bodies upon each other; particularly by the 
oxidation of metals, during which process, considerable 
quantities are evolved. 

3. It appears to be in a state of less intensity or con- 
densation than the electricity obtained by the electrical 
machine. 

4. It will oxidize metals, and set fire to all inflammable 
substances : it will also give a charge to a Leyden phial. 

5. Of all known substances, the nerves of animals, re- 
cently dead, appear to be the most easily affected by it ; 
and constitute electrometers of exquisite delicacy. 

6. It is conducted, and refused a passage by some 
substances, as common electricity. 

7. When a living animal forms a part of its circuit, it 
produces a sensation resembling that of the electric 
shock. 

8. Electricity is generated by the galvanic battery ; 
but only collected or transferred by the electrical ma- 
chine ; and, therefore, the effects of the former are in- 
creased by insulation. 

9. The power of galvanism in consuming wires, is 
greatest when the plates are numerous ; but in giving a 
shock, it is greatest when the plates are large, the quan- 
tity of surface in each case being the same. 



MAGNETISM. 

A PECULIAR species of attraction, excited by bodies 
called magnets or loadstones, receives the appellation of 
magnetism. 

Abstract of Magnetism. 

1. That principle which produces the phenomena of 
magnetism, is not cognizable by our senses, except by 
its effects ; but it is considered to be a fluid, and spoken 
of under the denomination of the magnetic fluid. 

2. Iron has been usually considered as the only sub- 
stance susceptible of magnetism ; but late investigations, 



MAGNETISM. 263 

which have been made with great care, have rendered 
it extremely probable that both nickel and cobalt like- 
wise submit to the influence of the same power. 

3. Magnets are either natural or artificial ; natural 
magnets are ores of iron, dug out of the earth in a mag- 
netical state ; artificial magnets are made of steel, by 
the help of a natural magnet. 

4. In every magnet there are two opposite points, 
which at all times and places, will, if the magnet be at 
liberty to move either without or with very little friction, 
turn to the poles of the world, or nearly so. 

5. It is this singular property, which is called polarity, 
that renders the magnet so useful in navigation. 

6. The poles of magnets, if of the same name, as 
when two north or two south poles are brought near 
together, repel each other; different poles, on the con- 
tra r)^ attract each other. The centre of a magnet 
neither attracts nor repels. 

7. The earth itself acts as a great magnet, the poles 
of which nearly but not quite coincide with the geo- 
graphical poles. 

8. It is this difference between the magnetical and the 
geographical poles, that produces the declination of the 
needle, which turns to the former, and only indicates the 
latter by the nearness of the two. 

9. The magnetical poles are not fixed points, but the 
cause of their motion is unknown. 

10. The constant change which the motion of the 
magnetic poles produces in the declination of the needle, 
is the cause of what is called the variation of the com- 
pass. 

11. At all places not 90 degrees from the magnetic 
poles, one pole of a magnet suspended by its centre sinks 
below the horizon, which is called the dip or inclination 
of the needle. 

12. In the northern hemisphere, it is the north pole 
which dips, and in the southern hemisphere it is the 
south pole. 

13. To render a natural magnet capable of lifting a 



264 PNEUMATICS. 

weight with the force of both poles, it is furnished with 
an armature ; an artificial nnagnet, for the same purpose, 
is made in the form of a horse-shoe. 

14. Soft iron receives magnetism with great facility, 
but loses it almost immediately : steel on the contrary, 
but especially hardened steel, is not easily affected ; but 
the portion it receives, it permanently retains. 

15. A magnet employed in the communication of 
magnetism, rather gains than loses strength. 

16. A steel bar, rendered magnetic, and resting by its 
centre upon a point, so as to be at liberty to turn in any 
direction, is, with the box which contains it^ and a card 
on which are written the names of the winds, called the 
mariner^s compass. 

17. The azimuth compass differs chiefly from the 
above in having two sights, through which may be seen 
the sun or any heavenly body, of which the azimuth is 
to be taken. 

18. The dipping needle is made by accurately sus- 
pending a bar of steel, in an unmagnetical state, on the 
pivots of an axis passing through its centre ; it is then 
magnetized, and dips according to the action of the north 
or south pole upon it 

PNEUMATICS. 

The science of Pneumatics treats of the density, pres- 
sure, and elasticity of the air, and the effects which they 
produce. 

Pneumatics, being a science somewhat remote from 
the present design of this work ; and having the proper- 
ties of the air, under the head of chemistry ; we shall, 
therefore, let an abstract of this science suffice. 

Abstract of Pneumatics, 

1. The air is the fluid which w^e breathe ; with the 
vapours it contains, it is called the atmosphere. 

2. The particles of air are solid and impermeable, like 
those of the hardest bodies. 



PNEUMATICS. 265 

3. The air is invisible, because of its great trans- 
parency; when unconfined it is imperceptible to the 
touch, because its particles move among each other with 
a facility so great that we perceive no force to be 
required in displacing it ; we move in it as if we had no 
pressure upon us, because its pressure is in every direc- 
tion the same. 

4. The weight of air is to that of water, as 832 to 1. 

5. The air expands in proportion to the diminution of 
the pressure upon it ; it, therefore, becomes rare as we 
ascend in the atmosphere : at the height of 3|- miles, a 
given bulk of it takes up twice the space it would do at 
the surface of the earth. 

6. The air-pump is a machine for exhausting the air 
out of vessels ; but the best air-pumps have not so com- 
pletely attained their object as to produce an absolute 
Vacuum, or place void of air. 

7. The rising of water in common pumps, is owqng to 
the pressure of the atmosphere being removed from one 
part of the fluid, which, therefore, yields at that part by 
the pressure on the other parts, till the column of water 
sustained is equal to the column of air sustaining it. 

8. Suction, unless so applied as to mean the pressure 
of the atmosphere, is a non-entity, and incapable of pro- 
ducing effects. 

9. The pressure of the atmosphere, which is in gen- 
eral 15 lbs. on every square inch, is not invariably the 
same, but is in a middle-sized person 1866 pounds less at 
one time than another; and when the pressure is greatest, 
we feel exhilarated rather than depressed. 

10. On the variable pressure of the atmosphere, and 
the changes thereby occasioned, is founded the utility 
of the barometer, by which instrument the pressure is 
measured. 

11. The best barometer is the common one, with a 
straight tube, and short scale of variation ; other kinds, 
in contriving which, the extension of the scale of variation 
has been chiefly aimed at, are all more or less defective. 

12. In observations for measuring the height of moun- 

23 



260 PNEUMATICS. 

tains, a thermometer must be used along with the 
barometer, in order that the due allowance may be 
made for the effects of temperature in lengthening or 
shortening the column of mercury ; and the surface of 
the mercury in the cistern must be at a fixed distance 
from the scale, before the height of the mercury is 
read off, 

13. The air may be condensed, or forced into less 
compass than it occupies at the surface of the earth, by 
means of a contrivance called a condensing engine. 

14. When much condensed, the efforts of the air to 
expand are so great, that it may be employed as a 
powerful motive force. On this depend the properties 
of air-guns. 

15. An hygrometer is an instrument for measuring the 
dryness or moisture of the atmosphere. 

16. De Saussure's hygrometer is made of clarified hair; 
De Luc's, of a slip of whalebone cut across the grain. 

17. The depth of rain which falls on the earth is esti- 
mated by the quantity which falls within a small vessel 
called a rain-gauge, 

18. The strength of wind is measured by its power to 
support bodies out of the position of equilibrium. 

19. The winds are the consequences of variations con- 
stantly taking place in the density of the atmosphere, 
principally by the action of solar heat. 

20. Variable w^inds are supposed to be the chief 
causes of the rising and falling of the barometer, which, 
in countries not subject to them, remains almost uniformly 
at the same height. 

21. In deriving from the barometer, prognostics of the 
w^eather, the tendency of the mercury to an upward or 
downward motion, rather than its absolute height at any 
time, is chiefly to be regarded. 

22. When the air reaches the ear in a state of vibra- 
tory motion, it occasions the sensations of sound, 

23. Bodies which produce the clearest and strongest 
sound, are in general the most elastic. 

24. The quality of sound, in point of tone, is determi- 



OPTICS. 267 

ned by the greater or smaller number of vibrations made 
by the sounding body in a given time. 

25. Sonorous bodies, when sufficiently near, cause 
each other to sound, although but one of them is struck, 
provided they be in unison, or disposed to make vibra- 
tions equally frequent. 

26. An echo is the reflection of a sound, and cannot 
be heard unless the original sound has traversed the 
distance of about 110 feet. 

27. Speaking and hearing trumpets act upon the 
principle of reflecting tow^ards their axes, and thereby 
concentrating the sound transmitted through them. 

OPTICS. 

This is a branch of Natural Philosophy which treats 
of the mechanical properties of light, and the phenomena 
of vision. 

Abstract of Optics, 

1. The particles of light, which are inconceivably 
small, proceed from luminous bodies in right lines. 

2. Consequently the density of light is inversely as the 
square of the distance from the luminous centre. 

3. Light moves at the rate of nearly 200,000 miles in 
one second of time. 

4. Its impression on the retina is not instantaneous; 
hence though its particles may be separately projected, 
so as to be, in their progress, at the rate of 1000 miles 
apart, its velocity is sufficient to produce a distinct vision. 

5. Every ray of light carries with it the image of the 
point from which it was emitted ; when, therefore, pen- 
cils of rays from every point of an object are united in 
the same order in which they were emitted, they form 
an image or representation of that object, at the place 
where they are thus emitted. 

6. All the rays of light, which enter another medium 
obliquely, suflfer refraction; that is, they either move 
farther from, or nearer to, the perpendicular, as the 



268 OPTICS. 

medium into which they enter is rarer or denser than 
the other medium. 

7. On the refrangibility of light depends the proper- 
ties of lenses. 

8. Convex lenses collect the rays of light, and make 
them converge to a centre or focus. 

9. Concave lenses disperse the rays of light, the pourer 
of refraction not being towards the centre, but towards 
their circumference. 

10. When light strikes upon a surface, it is reflected 
so that the angle of reflection is equal to the angle of 
incidence ; on this the properties of mirrors depend. 

11. Plane mirrors have no other effect than that of 
changing the direction of the incident rays. 

12. Convex mirrors cause parallel rays to diverge. 

13. Concave mirrors collect parallel rays, or cause 
them to converge to a focus. 

14. Mixed mirrors exhibit distorted images, because 
they increase or lessen the divergence or convergence of 
the rays in one or two directions only. 

15. The solar beam is composed of rays possessed of 
different degrees of refrangibility, and these differences 
of refrangibility, which are dependent on the size of 
their particles, produce all the phenomena of colours. 

16. The solar beam, or white light, contains rays of 
seven diflferent colours, viz. red, orange, yellow, green, 
blue, indigo, and violet. These are called the primitive 
colours, because they are immutable, except by inter- 
mixture. 

17. It is inferred that red light is composed of par- 
ticles of the largest size, because it is found to be 
capable of struggling through thick and resisting mediums, 
w^hich stop every other colour. 

18. The size of the particles of other colours is in 
the order of their enumeration, the violet being the 
smallest. 

19. The rainbow is owing to the separation of the 
light into its primitive colours, by the drops of falling 
rain, which act like a prism. 



OPTICS. 269 

20. The rays of light are inflected when they pass 
very near a body, and deflected when they pass at a 
greater distance. 

21. Those rays which deviate the least by refraction, 
deviate the most by flection. 

22. The images of all visible objects are depicted on 
the retina, in an inverted position. 

23. With two eyes, vision is not only more distinct, 
but more accurate than with one. 

24. A good eye can see most distinctly \then the rays 
fall exactly on the retina. 

35, The best eye can hardly distinguish any object 
that subtends an angle of less than half a minute. 

26. The apparent magnitude of objects is dependent 
on the angle under which they are seen, or the size of 
their images depicted on the retina. 

27. The long-sighted require convex spectacles, the 
short-sighted, concave ones. 

28. Burning lenses must be convex, and burning mir- 
rors concave, as the effects of both these instruments 
are dependent on the condensation of the incident light. 

29. Microscopes are optical instruments for viewing 
small objects. They appear to magnify objects, because 
they enable us to see them with distinctness, nearer than 
the 'natural Hmits of vision. 

30. Refracting telescopes are formed by lenses only ; 
when manufactured in the best manner, they are either 
furnished with an acromatic object-glass, which corrects 
the defect arising from the unequal refraction of the 
different rays, by a combination of one or two convex 
lenses with a concave one of a different sort of glass; or, 
though more rarely, they have an aplanatic object- 
glass, which corrects the same defect by a combination 
of a plano-convex and meniscus glass, with a fluid be- 
tween them that ^cts like a third lens. 

31. Reflecting telescopes consist of lenses and at least 
of one speculum. When there is more than one specu- 
lum, the second is only about one-fourth of the size of 
the other, and may be either convex, concave, or plane. 

23* 



270 ASTRONOMY. 

32. Reflecting telescopes admit of a much greater 
magnifying power in a given length, than refracting 
telescopes. 

33. The hinocular telescope consists of two telescopes 
so combined, that both eyes may be employed in looking 
at the same object. 



ASTRONOMY 

Is the science which treats of the motions, eclipses, 
magnitudes, periods, and other phenomena of the heaven- 
ly bodies. 

Abstract of Astronoiny. 

1. The solar system comprises the sun and all the 
bodies that revolve around him, viz : the comets, the 
planets with their respective satellites, and the asteroids. 

2. The number of the comets is unknown ; that of 
the planets, so far as yet discovered, is seven ; the satel- 
lites eighteen ; and the asteroids four. 

3. The figure of the earth is not that of a perfect 
globe, but an oblate spheroid, flattened a little at the 
poles, by its revolution on its axis. 

4. The planets Jupiter and Saturn are also observed 
to be flattened at the poles like the earth, but in a great- 
er degree, evidently because their diurnal revolution is 
swifter. 

5. The orbits of all the planets, asteroids, and comets, 
are ellipses, having the sun in one of their foci; but the 
orbits of the two former classes of bodies are nearly 
circular, while the orbits of the comets are all very 
eccentric. 

6. The orbits of the satellites are also ellipses, in one 
of the foci of w^hich is sustained the primary planet 
round which they move. 

7. The periods, distances, and magnitude of the planets, 
have all been determined with very considerable exact- 
ness; the same circumstances respecting the asteroids, 



ASTRONOMY. 271 

are also evidently determinable, though the results yet 
laid down, have not, from the recept date of their dis- 
covery, been so amply confirmed, as to be fully relied on; 
but the comets recede to such immense distances, and 
there is so much uncertainty in identifying them, that 
their elements are hypothetical. 

8. The planets, comets, and asteroids, are preserved 
in their orbits, by the joint effects of the power of attrac- 
tion, which acts in a right line from them to the sun, and 
a projectile or centrifugal force, which would carry them 
off in a tangent to the curve of revolution, 

9. The powers which preserve the satellites in their 
orbits, are the same as those that act upon the planets 
and comets, but the centripetal force is exercised by the 
primary. 

10. The body of the sun is supposed to be opaque, 
and to be surrounded with a double set of clouds, the 
upper stratum of which forms the luminoijs globe we 
behold. 

11. The planets revolve round an imaginary line or 
axis within themselves, and the time in which they per- 
form this rotation, constitutes their day and night. 

12. The time in which a planet revolves round the 
sun, forms its year. 

13. The diversity of seasons is occasioned by the incli- 
nation of the axes of a planet to the plane of its orbit. 

14. The annual and diurnal revolutions of the planets 
are all performed from west to east. 

15. The satellites, also, revolve from west to east, with 
the exception of the satellites of Herschel, which appear 
to move in a contrary direction. 

16. The fixed stars are distinguished from the bodies 
of the solar system, by the twinkling light they afford, 
by their having no parallax, and by their having, even 
through the best telescopes, no sensible magnitude. 

17. The naked eve cannot behold above five hundred 

^ »/ . 

stars in the whole hemisphere ; but the number dis- 
covered with the assistance of a telescope exceeds alj 
calculation. 



272 ASTRONOMY. 

18. Every fixed star is supposed to be a sun, shining 
by its own light, and surrounded by planetary worlds 
like those of the solar system. 

19. The tides are an effect of the attraction of the 
sun and moon upon the ocean. When these luminaries 
act together, or in the same line, they occasion spring 
tides ; when they counteract each other's attraction, 
neap tides take place. 

20. Eclipses of the moon are owing to the shadow of 
the earth falling upon the moon. 

21. Eclipses of the sun occur, when the moon coming 
between the earth and the sun, throws a shadow^ on the 
earth. 

22. Motion is the measure of time, and the motions of 
the heavenly bodies are the basis by which all other 
motions are measured. 

23. The day is a natural division of time, that is, it 
comprises a portion of time measured out by the com- 
pletion of certain phenomena, successive according to 
regular laws. 

The periodical and synodical lunar months are also 
natural divisions of time, but no other ; the year, and 
lunar and solar cycles, are of the same character as the 
lunar months ; the cycle of indiction, and the olympiad, 
are examples of the artificial division of time. 

Thirty days hath September, 

April, June, and November; 

All the rest have thirty-one, 

Except the leap-year : that 's the time, 

When February's days are twenty and nine, 



MECHANICAL EXERCISES. 



OF IRON. 

Or all metallic substances, iron is the most abundantly 
diffused, and the most intrinsically valuable. 

(This metal is described under the head of Chemistry.) 

Iron is employed in three states, viz: that oi cast iron, 
wrought iron, and steel. Cast iron is the metal in its 
first state, rendered fusible by its combination with those 
two substances which chemists distinguish by the names 
carbon and oxygen. In the great iron works, the ore, 
broken in small pieces, and mixed with a portion of 
limestone to promote its fusion, is thrown into a furnace, 
which is from 16 to 30 ieet high. Baskets of charcoal 
or coke, in due proportion, are thrown in along with it. 
A part of the bottom of the furnace is filled with fire 
only. This being kindled, the whole is roused, by the 
blast of the great bellows, to a most intense heat. The 
metal, as it is reduced, sinks dow^n through the fuel, and 
collects at the bottom of the furnace. More ore and 
fuel are supplied above, and the operation goes on, till 
the melted metal, increasing in quantity, rises almost to 
the aperture of the blast ; a passage is then made for it 
at the side of the furnace, and it is run into what is 
called pigs of cast iron. A furnace will furnish daily 
from two to five tons of iron, according to the richness of 
the ore, and the skill with which the operation is con- 
ducted. Ores of iron are combined with magnesia, are 
very refractory, and, as well as those which contain sul- 
phur and arsenic, require to be roasted before they are 
cast into the smelting furnace. 

Pig-iron is of very different qualities; that which is 
called No. 1, and the fracture of which is of a dark 
colour, runs so fluid as to be admirably suited for grates, 
and ornamental work. Cast-iron cutlery is manufactured 

(273) 



274 MECHANICAL EXERCISES. 

from it, as no other would run fine enough for the pur- 
poses to which it is appHed, such as forks and small 
scissors, fish-hooks and needles. These articles obtain, 
by anealing, a considerable degree of malleability, 
and are even capable of being welded. When great 
strength is required, as for large wheels, beams, pillars, 
or rail-ways, the iron w^hich contains a smaller propor- 
tion of carbon is preferable ; as that called No. 2. The 
proportion of carbon in cast iron varies, in the different 
sorts, from one-fifteenth to one twenty-fifth. Cast iron 
also frequently contains a portion of the phosphuret of 
iron ; in which case, it breaks of a white colour, and 
must, from its excessive hardness, be rejected for pur- 
poses which require it to be filed, or turned, or cut with 
the chisel. It may be observed, that the whiter the 
metal is, the harder it is, also ; whether these properties 
are owing to its quality, or the mode of its management. 

Crude or cast iron is converted into wrought iron, by 
keeping it in a state of fusion for a considerable time, 
and repeatedly stirring it in the furnace ; the oxygen 
and carbon which it contains, unite, and fly off in a state 
of carbonic acid gas, and as this takes place the iron 
becomes more infusible ; it gets thick or stiff in the fur- 
nace ; and the workmen know, by this appearance, that 
it is tija^e to submit it to the repeated action of the ham- 
mer, or the regular pressure of large steel rollers, by 
which the parts which still partake of the nature of 
crude iron so much as to retain the fluid state, are forced 
out, and the metal is rendered malleable, ductile, more 
closely compacted, of a fibrous texture, and totally 
infusible. In this state it is known in commerce by the 
name of bar iron. The loss of weight sustained by iron, 
in the process of refining, is considerable, generally 
amounting to one-fourth, and sometimes to one-half 

Forged, like cast iron, varies greatly in its quality. 
Thus some of it is tough and malleable when it is hot 
and when it is cold. This is the iron in common use, 
and it is the best, and most useful. It may be known 
generally by the equable surface of the forged bar, which 



MECHANICAL EXERCISES. 275 

is free from transverse fissures, or cracks in the edges ; 
and by a clear white, small grained, or rather fibrous 
texture. The best and toughest iron is that which has 
the most fibrous texture, and is of a clear greyish colour. 
This fibrous appearance is given by the resistance which 
its particles make to separation. The texture of the 
next best iron, which is also malleable in all tempera- 
tures, consists of clear whitish small grains, intermixed 
with fibres. Another kind is tough when it is heated, 
but brittle when cold. This is called cold-short-iron, and 
is distinguished by a texture consisting of large shining 
plates, without any fibres. It is less liable to rust than 
any other description of forged iron. A fourth kind of 
iron called hot-short, is extremely brittle when hot, and 
malleable when cold. On the surface and edges of the 
bars of this kind of iron, transverse cracks or fissures 
may be seen, and its internal colour is dull and dark. 

The quality of iron may be much improved by violent 
compression, as by forging and rolling, especially when it 
is not long exposed to violent heat, which injures and at 
length destroys its metallic properties. But though iron 
is rendered malleable by hammering, this operation may 
be continued so long as to deprive it of its malleability. 

Steel is made of the purest malleable iron, by a pro- 
cess called cementation. In this operation, layers of bars 
of malleable iron, and layers of charcoal, are placed one 
upon another, in a proper furnace, the air is excluded, 
the fire raised to a considerable degree of intensity, and 
kept up for 8 or 10 days. If, upon the trial of a bar, 
the whole substance is converted into steel, the fire is 
extinguished, and the whole is left to cool for 6 or 8 days 
longer. Iron thus prepared is called blistered steel, from 
the blisters which appear on its surface. In England, 
charcoal alone is used for this purpose ; but Duamel 
found an advantage in using from one-fourth to one-third 
of wood-ashes, especially when the iron w^as not of so 
good a quality as to afford steel possessing tenacity of 
body as well as hardness. These ashes prevent the 
steel-making process from being effected so rapidly as it 



276 MECHANICAL EXERCISES. 

would otherwise be, and give the steel pliability without 
diminishing its hardness. The blisters on the surface of 
the steel, under this management, are smaller and more 
numerous. He also found that if the bars, when they 
are put into the furnace, be sprinkled with sea salt, this 
ingredient contributes to give body to the steel. If the 
cementation be continued too long, the steel becomes 
porous, brittle, of a darker fracture, more fusible, and 
capable of being welded. On the contrary, steel cement- 
ed with earthy infusible powders is gradually reduced 
to the state of forged iron again. Excessive or repeated 
heating in the forge is attended with the same effect. 

The properties of iron are remarkably changed by 
cementation, and it acquires a small addition to its 
weight, which consists of the carbon it has absorbed from 
the charcoal, and mounts to about the hundred-and- 
fiftieth, or two-hundreth part. It is much more brittle 
and fusible than before | and it may still be welded like 
bar-iron, if it has not been fused or over-cemented ; but 
by far the most important alteration in its properties is, 
that it can be hardened or softened at pleasure. If it 
be made red-hot, and instantly cooled, it attains a degree 
of hardness which is sufficient to cut almost any other 
substance; but, if heated and cooled gradually, it be- 
comes nearly as soft as pure iron, and may, with much 
the same facility, be manufactured into any determined 
form. A rod of good steel, in its hardest state, possesses 
so little tenacity, that it may be broken almost as easily 
as a rod of glass, of the same dimensions. This brittle- 
ness can only be diminished by diminishing its hardness; 
and in the proper management of this point, for different 
purposes, consists the art of tempering. The colours 
which necessarily appear on the surface of the steel, 
slowly heated, are yellowish-white, yellow, or straw 
colour^ gold colour, brown, purple, violet, and deep blue. 
These signs direct the artist in reducing the hardness of 
steel to any particular standard. If steel be too hard, it 
will not be proper for tools which are intended to have 
a fine edge, because it will be so brittle, that the edge 



MECHANICAL EXERCISES. 277 

will soon become notched : if, on the contrary, it be too 
soft, it is evident that the edge will turn or bend. Some 
artists inclose the tools to be hardened in an iron case or 
box, and slowly heat them to ignition ; they, then take 
the box out of the fire, and drop the pieces into water, in 
such a manner as will allow them to come as little as pos- 
sible into contact with the air. This method answers two 
good purposes; it causes the heat to be more equally 
applied, and prevents the scaling occasioned by the con- 
tact of air. When the work has been polished, and 
well defended from the air, it is, when hardened, nearly 
as clear as before. If the tool be unpolished, they 
brighten its surface upon a stone. It is then laid upon 
burning charcoal, or upon the surface of melted lead, or 
upon an ignited bar or plate of iron, till it appears the 
desired colour; atvvhich instant, they plunge it into cold 
water. The yellowish-white indicates a temper so little 
reduced as to be used for edge-tools; the yellow, or straw 
colour, the gold colour, and the brown, are used for pen- 
knives, razors, and gravers ; the purple, for tools used in 
working upon metals, especially iron ; the violet, for 
springs, and for instruments for cutting soft substances, 
such as cork, leather, and the like ; but if the last blue 
be waited for, the hardness of the steel will scarcely 
exceed that of iron. When soft steel is heated to any 
of these colours, and then plunged into water, it does not 
acquire nearly so great a degree of hardness as if pre- 
viously made quite hard, and then reduced by temper- 
ing. The degree of ignition required to harden steel is 
of different kinds. The best kinds require only a low 
red heat. It has been ingeniously supposed, that the 
hardness of steel depends on the intimate combination of 
its carbon ; and, on this supposition, it follows, that the 
heat which effects this is the best, and that a higher de- 
gree will be injurious. 

The texture of steel is rendered uniform by fusion. 
When it has undergone this operation, it is called cast- 
steel ; which is wrought with more difficulty than com- 
mon steel, because it is more fusible, and is dispersed 
24 



278 MECHANICAL EXERCISES. 

under the hammer, if heated to a white heat. The cast 
steel of England is made from the fragments of the 
crude steel of the manufactories and steel works. A 
crucible, ^bout ten inches high and seven inches in dia- 
meter, is filled with the fragments, and placed in a 
wind furnace, like that of the foundries, but smaller, 
because intended to contain one pot only. It is, like- 
wise, furnished with a cover and chimney, to increase 
the draught of the air. The furnace is entirely filled 
with coke, and five hours are required for the perfect 
fusion of the steel. It is then cast into ingots, and after- 
wards forged in the same manner as other steel, but with 
less heat and more precaution, as it is more liable to 
break. Cast steel is becoming more and more in use, 
but must necessarily be excluded from many works of 
considerable size, on account of the difficulty of welding 
it, and the facility with which it is degraded in the fire. 
Cast steel takes a fine firm edge, and receiving an 
exquisite polish, of which no other sort of steel is, in so 
high a degree, susceptible, it is made use of for all the 
finest cutlery in England ; it is too imperfectly fluid to 
be cast into small wires. The tenacity of steel ham- 
mered at a low heat, or even when cold, is considerably 
increased ; but the eflfect of the hammering is taken off 
by strong ignition. Tools, therefore, made of cast steel, 
and intended to sustain a good edge, for cutting iron and 
other metals, are not afterwards softened, but the ignition 
is carefully regulated at first, as the most useful hardness 
is produced by that degree of heat which is just suf- 
ficient to effect the purpose. Cast steel, annealed to a 
straw colour, is softened nearly as much as other kinds to 
a purple or blue. 

Various methods of hardening steel are resorted to, 
such as oil, tallow, urine, and other saline liquids; soap 
in solution produces a similar effect. But when steel is 
required to possess the greatest degree of hardness, it 
may be quenched in mercury, which will render it so 
hard as to cut glass like a diamond. 

Wrought iron may be hardened, in a small degree, by 



MECHANICAL EXERCISES. 279 

ignition and plunging into water, but the effect is con- 
fined to the surface ; except, as very often happens, the 
iron contains veins of steel. 

The surest method for selecting steel for edge tools, is, 
to have one end of the bar drawn out under a low heat, 
such as an obscure red, and then to plunge it suddenly, 
at this heat, into a pure cold water. If it prove hard, 
for instance, if it will easily cut glass, and require a 
great force to break it, whatever its fracture may be, it 
is good, the excellence of steel being always proportion- 
ate to the degree of its tenacity in its hard state : in 
general a neat curved line fracture, and even grey tex- 
ture, denote good steel, and the appearance of threads, 
cracks, or brilliant specks, is a proof of the contrary. 

If diluted nitrous acid (aquafortis) be applied to the 
surface of steel previously brightened, it immediately 
produces a black spot, but if applied to iron, in like 
manner, the metal remains clear. By this method it 
will be easy to select such pieces of iron or steel as pos- 
sess the greatest degree of uniformity ; as the smallest 
vein of either upon the surface, will be distinguished by 
its peculiar sign. 

The hardness and polish of steel may be united, in a 
certain degree, with the firmness and cheapness of 
malleable iron, by what is called case-hardening, an 
operation much practised, and of considerable use. It 
is a superficial conversion of iron into steel, and only 
difiers from cementation in being carried on for a shorter 
time : some artists pretend to great secrets in the prac- 
tice of this art, using saltpetre, sal ammoniac, and other 
fanciful ingredients, to which they attribute their success. 
But it is now an established fact, that the greatest effect 
may be produced by a perfectly tight box, and animal 
carbon alone. 

The goods intended to be case-hardened, being pre- 
viously finished with the exception of polishing, are 
stratified with animal carbon, and the box containing 
them luted with equal parts of sand and clay. They 
are then placed in the fire, and kept in a light-red heat 



280 MECHANICAL EXERCISES. 

for half an hour, when the contents of the box are 
emptied into water. Delicate articles may be preserved 
like files, by a saturated solution of common salt with 
any vegetable mucilage to give it a pulpy consistence. 
The carbon here spoken of, is nothing more than any 
animal matter, such as horns, hoofs, skins, or leather, 
just sufficiently burnt to admit of being burnt to powder. 
The box is commonly made of iron, but the use of it, 
for occasional case-hardening upon a small scale may be 
easily dispensed with ; as it will answer the same end to 
envelope the articles with the composition above direct- 
ed to be used as a lute, drying it gradually, before it is 
exposed to a red heat, otherwise it will probably crack. 
It is easy to infer, that the depth of the steel induced by 
case-hardening, will vary with the time the operation is 
continued. In half an hour it will scarcely be the 
thickness of a six-cent piece, and therefore will be re- 
moved by the violent abrasion, though sufiicient to 
answer VA^ell for fire-irons, &c., in the common usage of 
which its hardness prevents its being easily scratched, 
and its polish is preserved by friction with so soft a ma- 
terial as leather. 

The blueing of steel has a remarkable influence on 
its elasticity. This operation consists in exposing steel, 
the surface of which has been brightened, to the regu- 
lated heat of a plate of metal, or of a fire, or lamp, till 
the surface has acquired a blue colour. If this blue 
colour, so commonly considered rather as ornamental 
than useful, be partially or wholly removed, by grinding, 
or in any other manner, the elasticity is proportionately 
impaired, and the original excellence of this property 
can only be restored by blueing the steel again. Saw- 
makers first harden their plates in the usual way, in 
which state they are brittle and warped ; they then 
soften them by blazing, which consists in smearing the 
plate with oil or grease, and heating it till thick vapours 
are emitted, and burn otF with a blaze. They then 
hammer them flat, and afterwards blue them on a hot 
iron, vi^hich renders them stiff and elastic, without alter- 
ing their flatness. 



MECHANICAL EXERCISES, 281 

Steel expands its dimensions, in a small degree, by 
hardening. It is a curious fact, that intense cold has 
an unfavourable effect on steel ; so that, in severe frosts, 
workmen often find their tools incapable of receiving the 
temper they wish. 

A slender rod of wrought iron may be expeditiously 
converted into steel, by plunging it into cast iron in fu- 
sion ; a satisfactory proof that cast iron contains the steel- 
making principle, vyhich, we need not repeat, is carbon. 
In fact, as it is principally in the superabundance of its 
carbon that it differs from steel, many attempts, (and 
not without success,) have been made to convert it into 
the latter, without the intermediate operation of render- 
ing it malleable. But the best steel made pursuant to 
this idea, is very imperfect. It is, however, not unim- 
portant to observe, that all cast iron so far resembles 
steel, as to be hardened in a high degree by sudden cool- 
ing, which imparts to it, at the same time, whiteness of 
colour, brittleness, and closeness of texture. This pro- 
perty of crude iron may be advantageously employed on 
many occasions ; for instance, in the fabrication of axles, 
and collars of wheels, which are closely turned or filed 
in a thin soft state, and may afterwards be hardened, so 
as to wear admirably well. 

The heat applied to cast iron, previously to its being 
plunged into the water to harden, is greater than that to 
w hich steel is subjected for the same purpose. Cast iron, 
also, vyhen once hardened, admits not, like steel, of that 
hardness being reduced, by various gradations, to any 
specific degree ; to soften it materially, it must be sub- 
mitted, for some time, to a complete ignition, and very 
gradually cooled. 

ANEALING. 

In a considerable number of instances, bodies which 
are capable of undergoing ignition, are rendered hard 
and brittle by sudden cooling. Glass, cast iron, and steel, 
are the most remarkably aflfected by this circumstance ; 
the inconveniences arising from which are obviated by 
24* ■ ' ' 



282 MECHANICAL EXERCISES. 

cooling them very gradually, and this process is called 
annealing. Glass vessels are carried into an oven over 
the great furnace called the leer, where they are per- 
mitted to cool, in a greater or less time, according to 
their thickness and bulk. Steel is most effectually 
anealed by making it red-hot in a charcoal fire, which 
must completely cover it, and be allowed to go out of its 
own accord. Cast iron, which may require to be an- 
nealed in too large a quantity, to render the expense of 
charcoal very agreeable, may be heated in a cinder fire, 
which must completely envelope and defend the pieces 
from the air till they are cold. The fire need not be 
urged so as to produce more thari a red heat; a little 
beyond this, bars and thin pieces would bend, if destitute 
of a solid support; and would even be melted without 
any vehement degree of heat. If it be required to aneal 
a number of pieces expeditiously, and the fire is not 
large enough to take more than one or two of them at 
once ; or if it be thought hazardous to leave the fire to 
itself, from an apprehension that the heat might increase 
too much, the following scheme maybe adopted: heat as 
many of the pieces at once as may be convenient, and 
as soon as they are red-hot, bury them in the dry saw- 
dust. Cast iron, when anealed, is less liable to warp 
by a subsequent partial exposure to moderate degrees 
of heat, than that which has not undergone this opera- 
tion. 

The above methods of anealing render cast iron easy 
to work, but do not deprive it of its natural character. 
Cast iron cutlery is, therefore, stratified with some sub- 
stance containing oxygen, such as poor iron ores, free 
from sulphur, and kept in a state little short of fusion for 
twenty-four hours. It is then found to possess a consider- 
able degree of malleability, and is not unfit for several 
sorts of nails and edge-tools. 

Copper forms a remarkable exception to the general 
rule of anealing. This metal is actually made softer 
and more flexible by plunging it, when red-hot, into cold 
water, than by any other me^ns. Gradual cooling pro- 
duces a contrary effect. 



MECHANICAL EXERCISES. 283 

COPPER. 

We refer to the article of chemistry for a minute enu- 
meration of the whole of the known metals; but in this 
place, we shall, with the exception of iron, which has 
already been noticed, introduce a general practical view 
of the properties, applications, and combinations with 
each other, of those most frequently occurring in common 
arts and common life. Making this our plan, the first 
object that claims our attention is copper. 

Copper is a very brilliant, sonorous metal, of a fine 
colour, possessing a considerable degree of hardness and 
elasticity. It is extremely malleable, and may be re- 
duced to leaves so fine, that they may be carried about 
by the wind. Its tenacity is very great. A wire of 
one-tenth of an inch in diameter will support a weight 
equal to 300 lbs. avoirdupois, without breaking. It does 
not melt till the temperature is elevated to about 27^ of 
Wedgwood; or, (by estimation) 14.50° of Fahrenheit. 
When rapidly cooled, it exhibits a granulated and porous 
texture. When the texture is raised beyond what is 
necessary for its fusion, it is sublimed in the form of visi- 
ble fumes. Its greatest malleability is at a low red heat. 
None of the malleable metals are so difficult to file,' or 
turn smooth, as copper; but it is cut by the graver, or 
ground by gritty substances, with great ease. 

When miners wish to know^ whether an ore contains 
copper, they drop a little nitric acid upon it ; after a 
little time, they drop a feather into the acid, and wipe it 
over the polished blade of a knife ; if there be the 
smallest quantity of copper in it, this metal will be pre- 
cipitated upon the knife, to which it will impart a pecu- 
liar colour. Roman vitriol, much used by dyers, and in 
many of the arts, is a sulphate of copper. A solution of 
this salt is used for browning fowling-pieces and tea-urns. 
In domestic economy, the necessity of keeping copper 
vessels perfectly clean, cannot be too strongly inculcated ; 
but it is worthy of remark that fat and oily substances, 
and vegetable acids, do not attack copper while hot ; and, 



284 MECHANICAL EXERCISER. 

therefore, copper vessels may be used, for culinary pur- 
poses, with perfect safety, if no liquor be ever suffered 
to grow cold in them. The mere tinning of copper and 
brass vessels does not afford complete safety, as it is never 
so perfect as to cover every part. 

Compounds formed by the mixture of two or more 
different metals are called alloys. The alloys of copper, 
especially those in which this metal predominates, are 
more numerous in the arts than those of any other 
metal. Many of them are perfectly well known, and have 
been immemorialiy in use. The exact composition, and 
particularly the mode of preparing several, are kept as 
secret as possible. By the aid of chemistry, we may 
detect the exact composition of an alloy; yet we may 
not always be able, by common methods, to produce a 
mixture having all the excellencies, which perhaps, 
mere accident has taught the possessor of the secret to 
combine. 

Brass is the most important of all the alloys of copper. 
It is more fusible than copper, less liable to tarnish from 
exposure to the atmosphere, and its fine yellow colour is 
more agreeable to the eye. It is much more malleable 
than copper, when cold, but less malleable when hot; at 
a low red heat, it crumbles under the hammer. Sieves 
of extreme fineness are woven with brass wire, after the 
manner of cambric weaving which could not jwssibly be 
made with copper wire. Three parts of copper and one 
of calamine, or native carbonate of zinc, constitute brass. 
The calamine is first pounded in a stamping mill, and 
then washed and sifted, in order to separate the lead 
with which it is mixed. It is then calcined on a broad, 
shallow brick earth, over an oven heated to redness, and 
frequently stewed for some hours. In some places, it is 
calcined in a kind of kiln, filled with alternate layers of 
calamine and charcoal, and kindled from the bottom, 
where a sufficient quantity of wood has been deposited 
for the purpose. When the calamine has been thoroughly 
calcined, it is ground in a mill, and mixed at the same 
time with a third or a fourth part of charcoal, and is 



MECHANICAL EXERCISES. 285 

then ready for the hrass furnace. Being put into cru- 
cibles with the requisite proportion of grain copper, 
copper chippings, or refuse bits of various kinds, the 
whole is covered with charcoal, and the crucibles luted 
up with a mixture of clay or loam and horse-dung. The 
heat employed, is, for a considerable time, not sufficient 
to melt the copper, which is at length raised so as to 
fuse, and the compound metal is then run into ingots. 

In general, the extremes of the highest and lowest 
proportions of zinc are from twelve to twenty-five per 
cent, of zinc ; brass is perfectly malleable, if well man- 
ufactured, though zinc itself scarcely yields to the hammer 
at common temperatures. 

Good brass, when received from the foundry, is nearly 
inelastic, but exceedingly flexible, and when polished, 
the naked eye cannot discover any pores, which are fre- 
quently observable in the inferior kinds. The liberal 
use of the hammer imparts a considerable portion of 
elasticity to brass, and renders it at the same time less 
flexible. Clock-makers, watch-makers, and all artists who 
employ this metal, put it in forms that admit of hammer- 
ing it well before they turn or file it ; otherwise their 
work w^ould wear indifferently, and a trifling cause injure 
its figure. Brass is not malleable v^hen ignited. 

Hammering is found to give a magnetic property to 
brass, perhaps occasioned by the minute particles of iron 
separated from the hammer and the anvil during the 
process, and forced into its surface. This circumstance 
makes it necessary to employ unhammered brass for 
compass boxes and similar apparatus. 

Five or six parts of copper and one of zinc, form a 
pinchbeck. Tombac has still more copper, and is of a 
deeper red than pinchbeck. Prince's metal is a similar 
compound, excepting that it contains more zinc than 
either of the former. 

The alloys of copper with different proportions of tin, 
are of great importance in the arts. They form com- 
pounds which have dis;tinct and appropriate uses. Tin 
renders copper more fusible, less liable to rust, harder, 



286 MECHANICAL EXERCISES* 

denser, and more sonorous. Copper and tin separately, 
are not more remarkable for their ductility, than, when 
united, the compounds they form are for their brittleness. 

Eight to ten parts of tin, combined with one hundred 
parts of copper, form bronze, which is of a greyish 
yellow colour, harder than copper, and the usual compo- 
sition for statues. 

The customary proportions for bell-metal are, three 
parts of copper and one of tin. The greater part of the 
tin may be separated by melting the alloy, and then 
throwing a little water upon it. The tin decomposes the 
water, is oxidized, and thrown upon the surface. The 
proportion of tin in bell-metal is varied a little at differ- 
ent foundries, and for different sorts of bells. Less tin is 
used for large bells than smaller ones, and for very small 
ones, a trifling quantity of zinc is used, which renders 
the composition uiore sonorous, and it is still further 
improved in this respect by a little silver being added. 

A small quantity of antimony is occasionally found in 
bell-metal. When copper, brass, and tin, are used to 
form bell-metal, the copper is from seventy to eighty per 
cent, including the proportion contained in the brass, and 
the remainder is tin and zinc. When tin is nearly one- 
third of the alloy, it is then beautifully white, w^ith a 
lustre almost like mercury, extremely hard, close-grained, 
and brittle ; but when the proportion of tin is one-half, 
it possesses these properties in a still more remarkable 
degree, and is susceptible of so exquisite a polish, as to 
be admirably adapted for the speculums of telescopes. 
If more tin be added than amounts to half the weight 
of the copper, the alloy begins to lose that splendid 
whiteness for which it is so valuable as a mirror, and 
becomes of a blue grey. As the quantity of tin is in- 
creased, the texture becomes rough-grained, and totally 
unfit for manufacture. 

OF TIN. 

Tin is a metal of considerable importance in the arts. 
It is of a silver- white colour, very ductile, malleable, and 



MECHANICAL EXERCISES. 287 

gives out while bending, a peculiar crackling noise. Its 
specific gravity is 7.291 ; a cubic foot weighs about 
516 lbs. avordupois. Its purity is in proportion to its 
levity. It melts at the 400th degree of Fahrenheit's ther- 
mometer, and promotes the fusibility of the metals with 
which it is mixed. Two parts lead and one of tin form 
plumbers' solder, which melts sooner than either of the 
metals separately. Eight parts of bismuth, five of lead, 
and three of tin, fornri a metal which melts at a heat 
not exceeding that of boiling water. 

Tin is used to form boilers for dyers, and worms for 
rectifiers' stills. The common mixture for pewter is 112 
lbs. of tin, 15 lbs. of lead, and 6 lbs. of brass. But the 
name of pewter is given to any malleable white alloy 
into which tin largely enters ; and perhaps no two manu- 
facturers employ the same ingredients in the same pro- 
portions. The finest kinds of pewter contain no lead 
whatever ; but consist of tin, with a small quantity of 
antimony, and sometimes, a little copper. Pewter may 
be used for vessels containing wine, and even vinegar, 
provided the tin constitutes three-fifths of the alloy. 

The consumption of tin, in the operation called tinning,* 
is very considerable. The principal secret in tinning is, 
to preserve the tin and surface of the metal to which it 
is intended to be applied, perfectly clean, and in a pure 
metallic state. Thin plates or sheets of iron, which, 
when coated with tin, are so well known under the 
name of tin-plates, white iron, or latten, are prepared by 
scouring them with sand. They are then immersed in 
water, acidulated with sulphuric acid, in which they are 
kept for twenty-four hours, being occasionally turned 
during that time, so that they may rust equally in every 
part. When taken out, they are scoured, and made 
perfectly clean ; they are then dipped in pure water, 
and kept till wanted for tinning. The tin is melted in 
an iron crucible, narrow, but deeper than the length of 
the iron plates, which are plunged in downright, so that 
the tin swims over them. The surface of the tin, to 
prevent its oxidation, is covered with some oily or resin- 
ous matter. 



288 MECHANICAL EXERCISES. 

Reaumur states, that the Germans cover it with suet, 
previously prepared by frying and burning, which sur- 
prisingly puts the iron in a condition to receive the tin. 
The melted tin must also have a certain degree of heat. 
If not hot enough, it will not adhere to the iron ; and, if 
it be too hot, the coat will be very thin, and the plates 
discoloured. Plates intended to have a very thick coat, 
are first dipped into the crucible when the tin is very 
hot, and afterwards, when it is cooler. For the second 
dipping, the suet must not be prepared, but used in its 
common state. The tin not only adheres to the surface 
of iron plates, but penetrates, and intimately combines 
with them. 

Copper is tinned after it has been formed into utensils. 
If the copper be new, its surface is first scoured with 
salt and diluted sulphuric acid; pulverised resin is then 
thrown over th^ interior of the vessel, into which, after 
heating it to a considerable degree, a sufficient quantity 
of melted tin is poured, und spread upon it, by means of 
a rod of hard-twisted flax -, which renders the coating 
uniform. Pure tin is rarely used for this purpose; it is 
• generally, though injuriously, alloyed with a small pro- 
portion of lead. The use of the resin is important ; for 
the heat given to the copper is sufficient to oxidize its 
surface in some degree ; and an alteration of this sort, 
however slight, would prevent the perfect adhesion of 
the tin. The resin is equally useful in preventing the 
partial oxidation of the tin, or in reviving the small par- 
ticles of oxide which may be formed during th^ ope- 
ration. 

For tinning old vessels a second time, the surface is 
first scraped clean and bright with a steel instrument, or 
scoured with iron scales, then pulverised salammoniac is 
strewed over it, and the melted tin is rubbed on the sur- 
face with a solid piece of salammoniac. 

The process for covering iron vessels with tin, corre- 
sponds w4th that last described ; but they ought to be 
previously cleaned with the muriatic acid, instead of 
being scraped or scoured. Iron nails which cannot be 



MECHANICAL EXERCISES. 289 

conveniently tinned in a bath, are easily covered vsuth tin 
by including them, with a due proportion of tin and 
salammoniac, in a stone bottle, and agitating them while 
heating and cooling. 

The follow^ing method of tinning is highly esteemed for 
its permanency and beauty : the utensil is cleaned in the 
usual manner ; its inner surface is beaten on a rough 
anvil, or scratched with a wire-brush, that the tinning 
may adhere more closely to the copper ; and one coat of 
fine tin is then laid on w^th salammoniac as above directed 
for tinning old copper. A second coat consisting of two 
parts of tin and three of zinc, must next be uniformly 
applied w^ith salammoniac, in a similar manner : the sur- 
face is now to be beaten; scoured with chalk and water; 
smoothed with a proper hammer ; exposed to a moderate 
heat ; and lastly dipped in melted tin. This sort of tin- 
ning effectually prevents the utensils from rusting. 

Pins are whitened by filling a pan wuth alternate lay- 
ers of them and grain-tin. A solution of super-tartrate 
of potass, (cream of tartar) is then poured upon them, 
and they are boiled for four or five hours. The tartaric 
acid first dissolves the tin, and then gradually deposits it 
on the surface of the pins, in consequence of its greater 
aflinity for the zinc which enters into the composition of 
the brass wire. 

There are two kinds of tin known in commerce ; viz. 
block tin, and grain tin. Block tin is procured from the 
common tin ore ; grain tin is found, in small particles, in 
what is called stream tin ore. It owes its superiority not 
only to the purity of the ore, but to the care with which 
it is washed and refined. 

OF LEAD. 

Lead unites with most of the metals. It has little 
elasticity, and is the softest of them all. Gold and silver 
are dissolved by it in a slight red heat; but, when the 
heat is much increased, the lead separates, and rises to 
the surface of the gold, combined with all heterogeneous 
25 



290 MECHANICAL EXERCISES, 

matters. This property of lead is made use of in the 
art of refining the precious metals. 

If lead be heated so as to boil and smoke, it soon dis- 
solves pieces of copper thrown into it: the mixture, 
when cold, is brittle. The union of these two metals 
is remarkably slight ; for, upon exposing the mass to a 
heat no greater than that in which lead melts, the lead 
almost entirely runs off by itself. This process, which 
is peculiar to lead with copper, is called eliquation. It 
has lately been discovered, that a certain preparation 
of lead may be mixed with the metal formerly used for 
white metal buttons, without injuring the appearance ; 
thus affording a considerable addition of profit to the 
manufacturer. 

The consumption of lead for water-pipes, cisterns, and 
to cover buildings, is very extensive. Sheet-lead is made 
by suflTering the melted metal to run out of a box through 
a long horizontal slit, upon a table prepared for the pur- 
pose. The table is generally covered with sand, and 
the box is drawn over it by appropriate ropes and pul- 
leys, leaving the melted lead behind, to congeal in the 
desired form. The requisite uniformity and thinness are 
given to these sheets, by rolling them between two cylin- 
ders of iron, acting upon the same principle as the cop- 
per-plate printing-press. 

The alloy of lead and antimony is used for printers' 
types. Chaptal made a great variety of experiments to 
^ascertain the best proportions of these metals to each 
other for this use. He always found four parts of lead 
and one of antimony form the most perfect composition. 
But, if the antimony be pure, one part of it, to seven or 
eight of lead, form an alloy too brittle to be extended 
under the hammer, and as hard as the generality of 
types. To give liardness to the lead, is not the only use 
of antimony in this composition. It renders the lead 
more fusible, more fluid when melted, and, as it expands 
in passing to a solid state, it is calculated to produce a 
sharper impression of the mould than could be easily 
obtained by lead alone. Antimony, (which in trade is 



MECHANICAL EXERCISES. 291 

sometimes called regulus of antimony, or regulus, only,) 
requires, when alone, much more heat for its fusion than 
lead, in combining with which metal, as it is little more 
than half its weight, it rises to the surface, and requires 
to be well stirred before it will incorporate. Different 
parts of the -same block of type-metal often possess dif- 
ferent degrees of hardness. In melting lead for shot, a 
small quantity of arsenic is added, to cause it to run into 
spherical drops. The arsenic is generally added in ex- 
cess to a small quantity of lead, which is covered and 
closely luted till the incorporation is complete. The 
compound is called slag, or poisoned metal. Ingots of 
this slag are then added to soft pig-lead, in such propor- 
tion as is found, upon trial, to cause it to drop in a globu- 
lar form. 

The surface of melted lead, as every one knows, be- 
comes quickly covered with a skin or pellicle, often 
assuming different lively hues at first, and subsequently 
increasing in quantity and darkness of colour. This 
effect is termed by chemists, oxidation, as it is occasioned 
by the action of oxygen of the atmosphere, the activity 
of which is greater in proportion to the heat of the lead, 
and wastes the metal so fast, that it becomes an object of 
importance to those who melt much lead, to check its 
formation, or to convert it, when formed, by the cheapest 
process into the metallic state again. A thick coating 
of ashes of any kind will check the formation of the 
oxide, and may be easily pushed back, when a quantity 
of lead must be taken out of the crucible or melting-pan. 
Charcoal, which is also a good covering for lead in the 
pan, will convert dross into metal, when assisted by a 
sufficient heat ; fat, oily, and bituminous substances in 
general, have a similar effect. Common resin answers 
exceeding well ; thrown in powder upon melted lead, 
and stirred about, it immediately converts the oxide into 
metal, causes the surface to shine like mercury, and if any 
thing remains, it is only a black dirt, with small globules 
of pure lead, skimmed off at the same time, yet mixed 
with it ; by throwing it into w^ater, stirring it thoroughly, 



292 MECHANICAL EXERCISES. 

and pouring off all that does not immediately sink, these 
grains may be separated. If part of what appears to 
be dirt, is found to be so heavy, as instantly to sink to 
the bottom of water, it may be suspected to be true dross 
or oxide, and may be revived by mixing it with charcoal, 
and exposing it to a considerable heat. It is always, 
however, more prudent and economical to use means of 
preventing the formation of oxide, than to bestow much 
time upon its revival. 

Lead becomes less fluid every time it is melted, and by 
much or frequent exposure to a high temperature, a 
state in which it is said to be rotten, is superinduced. 
To use new lead, and not melt it oftener, or expose it to 
a greater heat than is indispensable, are necessary pre- 
cautions to preserve this metal in its best state. Plumbers, 
when they cast it into sheets, strew common salt upon 
the table, to facilitate its spreading, when they are not 
using new lead, and are for that, or any other reason, 
apprehensive that it will not run well. 

The observations above recited on the management 
of lead, apply with equal propriety, to tin, antimony, 
zinc, bismuth, &c., and all the alloys of these metals 
with lead or each other. In fact, as lead is so much 
cheaper than the other metals just enumerated, the ob- 
ject of saving it from destruction is proportionately of 
less consequence. 

OF ZINC. 

Zinc is a very combustible metal, of a bluish, brilliant 
white colour. It seems to form the link between the 
brittle and the malleable metals. It is a modern dis- 
covery, that at a temperature of from 210'' to 300"" of 
Fahrenheit, it yields to the hammer, may be drawn into 
wire, or extended into sheets. After having been thus 
annealed, it continues soft, flexible, and extensible, and 
does not return to its partial brittleness; thus admitting 
of being applied to many uses for which zinc was for- 
merly deemed unfit. 

There can now be no difficulty in forming zinc into 



MECHANICAL EXERCISES. 293 

sheathing for the bottoms of ships, into vessels of capa- 
city, water pipes, and utensils for various manufactories. 
As an internal lining for ordinary vessels, instead of tin, 
it has been applied with success. It is much harder and 
cheaper than tin, and may be spread very uniformly. 

Zinc at a very elevated temperature, may be pulver- 
ized. It may also, like several other metals, be minutely 
divided, by pouring it, when in fusion, into water. These 
are the most convenient means of reducing it into small 
particles. Files have no consideralDTe action upon it ; 
besides, it wears and chokes them up in a short time. 
Zinc, in filings or small particles, is used to produce those 
brilliant stars and spangles which are seen in the best 
artifiw:ial fire-works ; but the filings of cast iron produce, 
at a cheaper rate, an effect scarcely inferior. 

Calamine, or lapis calaminarus, used in converting 
copper into brass, is found in masses and in a crj^stallized 
state, and is generally combined with a large portion of 
silex. It is a native oxide of zinc, combined w^ith car- 
bonic acid. Zinc is also found in an ore called blena, or 
as the miners term it, Black Jack. It is a sulphuret of 
zinc : in Wales, it was employed formerly in mending 
the roads. 

SOLDERING. 

To unite two pieces of the same or different metals, 
by fusing some metallic substance upon them, is called 
soldering. It is a general rule, that the solder should be 
easier of fusion than the metal to be soldered by it. It 
is, in the next place, desirable, though seldom absolutely 
necessary, nor always attempted, that the solder and the 
metal to which it is intended to be applied, should be of 
the same colour, and of the same degree of hardness and 
malleabilit3\ 

Solders are distinguished into two different classes, viz. 
the hard and the soft solders. For the hard solders, 
which are ductile, and admit of being hammered, some 
of the same sort of metal as that to be soldered, is, in 
the greatest number of instances, alloyed with some 
25* 



294 MECHANICAL EXERCISES. 

other which increases its fusibility. Some of the facts 
already detailed, respecting the metals, prove that the 
addition made with this view need not always be itself 
easier of fusion. 

The solder for platina is gold, and the expense of it 
will, therefore, contribute to hinder the general use of 
platina vessels, even in chemical experiments. 

The hard solder for gold, is composed of gold and 
silver: gold and copper; or gold, silver, and copper. 
Goldsmiths usually make four kinds, viz. solder of eight, 
in which, to seven parts of silver, there is one of brass 
or copper; solder of six, where only a sixth part is cop- 
per; solder of four, and solder of three. But many who 
may have occasion to solder gold, cannot encumber them« 
selves with these varieties. 

For general purposes, therefore, the following composi- 
tion may be provided ; melt tw^o parts of gold, with one 
of silver and one of copper ; stir the mass well to make 
it uniform, add a little borax in powder, and pour it out 
immediately. If cast into very thin narrow slips, it will 
be the more handy for subsequent use. To cleanse gold 
which has been soldered, heat it almost to ignition, let it 
cool, and then* boil it in urine and sal ammoniac. 

The hard solder for silver may be prepared by melting 
two parts of silver with one of brass. It must not be 
kept long in fusion, lest the zinc of the brass fly otT in 
fumes. If the silver to be soldered, be alloyed with 
much copper, the proportion of brass may be increased : 
for example, the following composition may be used ; four 
parts of silver and three of brass, rendered easy of fusion 
by a sixteenth part of zinc. Silver which has been sol- 
dered, may be cleaned by heating it, and letting it cool, 
as directed for gold, but it must be boiled in alum water. 

The hard solder for copper and brass, is a soft fusible 
sort of granulated brass, known to artists by the name 
of speltre. It consists of brass mixed with an eighth, 
or a sixth, or even one-half of zinc. The braziers use 
no other kind of hard solder. As speltre melts sooner 
than common brass, it serves for the solder of the latter 
as well as for copper. 



MECHANICAL EXERClBEti. 295 

Standard silver makes an excellent solder for brass. 
It is more fusible than speltre, proportionately easier to 
manage, and equally as durable. A slight demand for 
silver solder, may, to many, be supplied at a cheap rate, 
in consequence of the number of the small silver articles 
in use, and which are frequently wearing out. 

Iron may be soldered with copper, gold, or silver. 
Brass or speltre is most commonly used, and the opera- 
tion is then called brazing ; but a carbonate of the same 
metal, viz. the dark grey or most fusible sort of pig iron, 
called No. 1, is the most durable solder that can be used. 
The pig iron loses some brittleness, and the malleable 
metal becomes harder in the proximity of the parts 
soldered. 

The parts upon which hard solder is intended to ope- 
rate, are touched with a finely powdered borax moistened 
with water. They must, also, as in all soldering and 
tinning operations, be perfectly clean. The borax 
quickly running into a kind of glass, promotes the fusion 
of the solder, and preserves from oxidation the surfaces 
to which it is applied. The pieces intended to be sol- 
dered, are fastened together with iron wire, or secured 
by some contrivance having the same effect. Speltre 
being composed of so many grains, is apt to spread when 
the borax boils up ; but just as it becomes fused, the 
workmen bring it to the place where it is wanted, by a 
slender iron rod. The flame of a lamp, directed by a 
blow-pipe against the solder covering the intended joint, 
\yhich must be laid upon charcoal, is suflicient for small 
things. For large work, a common culinary fire may be 
made to effect the desired fusion, though a forge is still 
more convenient. The fire should not touch the work, 
nor the ashes be allowed to fall upon it. 

The soft solders melt easily, hut are partly brittle, 
and therefore cannot be hammered. The solder for lead 
is usually (:pmposed of two parts of lead and one of tin. 
Its goodness is tried by n^elting it, and pouring about the 
size of a crown-piece upon a table ; little shining stars 
will arise upon it, if it is good. By diminishing th§ 



296 MECHANICAL EXERCISES. 

proportion of lead, we form what is called stray solder : 
we may also increase the proportion, which is advisable 
when we wish to solder vessels for containing acids; 
because lead is not so easily corroded or dissolved as tin. 

The lining of tea-chests has been used for solder, as it 
sometimes comes mixed about the right proportion. 
These valuable portions of tea-lead may be distinguished 
by their brilliancy, having suffered little from oxidation ; 
also, when they principally consist of tin, by the crack- 
ling noise while bending; which is peculiar to this 
metal, and some of the alloys into which it largely 
enters. 

The solder for tin may consist of four parts of pewter, 
one of tin, and one of bismuth, or two parts of tin, and 
one of lead : the latter is a composition much used. 

The soldering-iron of the tin-plate workers is an ingot 
of copper, flattened at the point, in a pyramidal form : 
it is screwed or riveted to an iron stem fastened to a 
wooden handle. The copper is seldom more than four 
or five inches long, and when it is worn away, the same 
stem and handle are used for another piece. The bar 
of copper is prepared for use, by filing it bright, and tin- 
ning it; when sufficiently hot, it will melt and take up 
the solder, so as to afford a ready means of applying it 
to the intended juncture. Powdered rosin, and some- 
times pitch, is used along wdth the soft solders, to pre- 
serve the metals employed from oxidation. 

Tin-foil, applied between the joints of fine brass- work, 
first wetted with a solution of sal ammoniac, and held 
firmly together w^hile heated, makes an excellent junc- 
ture, care being taken to avoid too much heat. 

OF GLUE. 

To prepare glue, it must be steeped for a number of 
hours, over night, for instance, in cold water, by which 
means it will become considerably swelled and softened. 
It must then be gently boiled, till it is entirely dissolved, 
and of a consistence not too thick to be easily brushed 
over vv^ood. About a quart of water may be used to 



MECHANICAL EXERCISES. 297 

half a pound of glue. The heat employed in nnelting 
glue should not be more than is required to make water 
boil; and to avoid burning.it, the workmen, as is well 
known, suspend the vessel containing it in another vessel 
containing only water, which latter vessel is made in the 
form of a common tea-kettle without a spout, and alone 
receives the direct action of the fire. 

The circumstances most favourable to the best effects 
which glue can produce, in uniting two pieces of wood, 
are the following : that the glue should be thoroughly 
dissolved, and used boiling hot at the first or second melt- 
ing ; that the wood should be warm and perfectly dry ; 
and a very thin covering of glue be interposed at the 
juncture, and that the surfaces to be united, be strongly 
pressed together, and left in that state, in a warm but 
not hot situation, till the glue be completely hard. In 
veneering, and for very delicate work, the whole of these 
requisites, as they not only ensure the strongest, but the 
glue sets the soonest, should be combined in the opera- 
tion ; but on some occasions this is impossible, and, there- 
fore, the most essential must be regarded, such as the 
fitness of the glue, and dryness of the wood. When the 
faces of joints, particularly those that cannot be much 
compressed, have been besmeared with glue, which should 
always be done with the greatest expedition, they should 
be rubbed lengthwise one upon another, two or three 
times, to settle them close. 

When glue, by repeatedly heating it, has become of a 
dark and almost black colour, its qualities are impaired ; 
when newly melted, it is of a light ruddy brown colour, 
nearly like that of the dry cake held up to the light ; 
and while this colour remains, it may be considered fit 
for almost every purpose. Though glue which has been 
melted is the most suitable for use, other circumstances 
being the same, yet that which has been the longest 
manufactured is the best. To try the goodness of glue, 
steep a piece three or four days in cold water; if it 
swell considerably without melting, and when taken out 
resumes, in a short time, its former dryness, it is excel- 



298 MECHANICAL EXERCISES. 

lent. If it be soluble in cold water, it is a proof that 
it wants strength. 

A glue which does not dissolve in water, may be ob- 
tained by melting a common glue with the smallest 
possible quantity of water, and adding by degrees lin- 
seed oil rendered drying by boiling it with litharge ; ; 
while the oil is added, the ingredients must be well stirred 
to incorporate them thoroughly. 

A glue which will resist water, in a considerable de- 
gree, is made by dissolving common glue in skimmed 
milk. 

Finely lixiviated chalk added to the common solution 
of glue in water, constitutes an addition that strengthens 
it, and renders it suitable for boards, or other things 
which must stand the weather. 

A glue that will hold against fire or water, may be 
prepared by mixing a handful of quick-lime with four 
ounces of linseed oil: thoroughly lixiviate the mixture, 
boil it to a good thickness, and then spread it on tin plates 
in the shade ; it will become exceedingly hard, but may 
be dissolved over a fire, as ordinary glue, and is then fit 
for use. 

THE COMMON SLIDING RULE. 

The divisors inserted in the following table, and the 
few plain directions and examples given, will now render 
it capable of being applied to every purpose that any 
artificer can possibly want. And by taking a copy of 
the table upon a piece of parchment, and carrying it 
always in the pocket, these divisors will be at hand : and 
the weight or measure required may be obtained. 

Description of the lines upon the slide rule. 

Upon the sliding rule of this rule are four lines mark- 
ed A, B, C, and D. The three marked A, B, and C are 
double lines of numbers, one of which is upon the rule, 
and the other two are upon the slide. That marked D 
is a single line of numbers, commonly called the girt line. 



MECHANICAL EXERCISES. 299 

JVumeration, 

Thesf four lines are divided as follows : each of the 
double lines marked A, B, and C are figured 1, 2, 3, 4, 
5, 6, 7, 8, 9; then again 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 
at the end. And these figures may be increased or de- 
creased in the value, but always in a tenfold proportion, 
at pleasure; thus one at the beginning may be called 
either 1, or 10, or 100, or 1000, and then the one in the 
middle of the rule must be called 10, 100, 1000 or 10,000. 
Observe, from one to two is divided into 10 parts, and 
each tenth is subdivided into 5 parts, and from 2 to 3 is 
divided into ten parts, and each tenth into 2 parts, and 
from 3 to 4 and so on to 10 is divided into 10 parts only. 
The girt line, marked D, is figured 4, 5, 6, 7, 8, 9, 10, 
12, 15, 20, 25, 30, 35, and 40 at the end.— And the 
figures and divisors are valued in tenfold proportion, as 
above. 

As there have been so many books published for the 
use of this Rule, it is unnecessary to say much upon the 
subject; because when numeration is properly under- 
stood, any person, from these plain directions, may per- 
form any operation, in superficial and solid mensurations, 
that may be wanted in the common course of business, 
and, with the assistance of these divisors, may find the 
weight of any of the articles contained in the table. 



A TABLE OF DIVISORS 

For the use of the common single Sliding Rule. 

The first column contains the divisors for dimensions 
that are taken ieei long, feet wide, and feet thick. The 
second column is for dimensions that are taken ieet long, 
inches wide and thick. The third column is for dimen- 
sions that are taken inches long, inches wide, and inches 
thick. 

The fourth is a column of divisors for dimensions that 



300 



MECHANICAL EXERCISES. 



are taken feet long, and inches dian^eter. The fifth 
column is for dimensions that are taken inches long and 
diameter. 

The sixth is a column of divisors or diameters, taken in 
feet. The seventh column is for diameters taken ini 
inches. 



Cubic Inches 

Cubic Feet 

Wine Gallons 

Ale Gallons 

Water in lb 

Oil in lb 

Gold in lb 

Silver in lb 

Quicksilver in lb 

Brass lb ..M 

Copper lb 

Lead lb 

Wrought Iron 

Cast Iron and Speltre lb 

Tin lb 

Steel lb 

Marble lb 

Free-stone lb 

Brick lb 

Coal lb 

Dry Oak lb. ,. 

Mahogany lb 

Box lb 

Red Deal lb 



Square. 



1st. 

36 
625 

835 
102 

10 
108 
507 
938 
738 

12 

880 
129 
139 
137 
136 
370 
394 
495 
795 
108 
94 
968 
151 



2d. 



3d. 



518 
9 

12 

147 

144 

1565 

735 

136 

122 

174 

163 

126 

186 

2 

135 

183 

53 

57 

72 

114 

158 

136 

152 

22 



624 
108 
145 
176 
174 
189 

88 
157 
127 
207 
196 
152 
222 
241 
235 

22 
637 

69 
860 
138 
190 
164 
169 
263 



Cylinders. 


Globes. 


4th. 


5th. 


,6th. 


7th. 


660 


799 


625 


113 


114 


138 


119 


206 


153 


183 


16 


276 


188 


224 


196 


335 


184 


22 


191 


329 


199 


238 


207 


358 


96 


118 


939 


180 


173 


208 


173 


354 


132 


162 


141 


242 


221 


265 


23 


397 


207 


247 


214 


371 


162 


194 


169 


289 


235 


283 


247 


423 


254 


304 


265 


458 


25 


300 


261 


454 


233 


278 


239 


418 


725 


81 


72 


121 


728 


873 


755 


132 


92 


10 


95 


164 


146 


176 


151 


262 


2 


237 


208 


355 


175 


208 


18 


336 


194 


214 


186 


32 


285 


236 


,287 


501 



EXAMPLES. 

Example 1. Required the content in cubic inches of a 
piece of timber 2 feet long, 12 inches wide, and 12 
inches thick ; see the preceding table of divisors in the 
line of cubic inches, second column, and you will find 
the divisor for feet long, inches wide, and inches thick is 
518, set 2, which is the length upon B, to 518, the divi- 



MECHANICAL EXERCISES. 301 

sor upon A, against 12, which is the breadth and thickness 
upon D, 3456, which is the content in inches on C. 

Ex. 2. Having the dimensions of an unequal sided 
piece of timber given to find the mean square, which 
must be done in all cases where the breadth and thick- 
ness are unequal. What is the square of a piece of 
timber 16 inches broad, and four inches thick? Set 16, 
the breadth on C, to 16 on D, and against 4, the thick- 
ness on C is 8 inches the square on D. 

Ex. 3. Required the content of a piece of cast iron 
24 inches long and 12 square ; see the preceding table 
in the line cast iron and speltre, third column, is divisor 
241 ; set 24 on B to 241 on A, and against 12 on D is 
896 on C. 

Ex. 4. Required the weight of a piece of cast iron 
circular 24 inches and 12 diameter: see the preceding 
table, fifth column, in the line cast iron and speltre is 304 
the divisor; set length on B to the divisor on A, and 
against the diameter on D is 708 lbs. the content on C. 

Ex. 5. Required the weight of a ball or globe in cast 
iron 12 inches in diameter; see the preceding table, 
seventh column, in the line cast iron and speltre is 458, 
the divisor; set 12 the diameter on B to 458, the divisor 
on A, and against 12 inches diameter on D, is 235 the 
content on C. 

Ex. 6. Required the content of a piece of timber 1 
inch long and 12 inches diameter ; see the preceding 
table, in the line cubic inches, fifth column, under cylin- 
ders, the divisor is 799 ; set 1 inch, the length on B, to 
799 on A, and against 12 inches the diameter on D, is 
113, the content on C. Observe, when the slide stands 
in this position it is a table of areas of all circles, D being 
diameters, or the squares of diameters, and C being areas 
or superficial inches. 

Ex. 7. Required the content of a piece of land, 70 
yards long, by 70 wide ; set 4840 on A, the number of 
yards in an acre, to 70 the length on B, and against 70 
the width on A is 1.01 on B. 

Ex. 8. Required the content of a piece of land, 40 
26 



302 MECHANICAL EXERCISES. 

poles long, and 5 poles wide; set 160, the number of 
poles in an acre on A, to 40 the length on B, and against 
5, the width on A is 1.25 or 1 acre on B. 

Ex. 9. Required the diameter of a circle, whose area 
is equal an ellipsis or oval, 32 by 22 inches diameter ; 
set 32 on C, to 32 on D, and against 22 on C is 26.6 
nearly on D. 

Ex. 10. Required the side of a square, equal in pro- 
portion to a parallelogram or long square, 32 by 22 
inches ; set 32 on C to 32 on D, and against 22 on C is 
26.6 the mean proportion on D. 

Ex. 11. Required the content in roods of a piece of 
walling, 25 feet long, and 10 feet high; set 63, which is 
the number of feet in a rood on A, to 25 the length on 
B, and against 10, the height on A is 4 roods nearly on B. 

Ex. 12. Required the content in roods of a piece of 
walling, 876 [eet long, and 5 feet high ; set.272|, which 
is the area in feet of a rood on A, to 876 the length on 
B, and against 5, the height on A are 16 roods nearly 
on B. 

CRANE. 

Ex. 14. Required the power of a crane handle suf- 
ficient to balance a weight of 6000 lbs. hung on a pair 
of blocks 3 pulleys each, the wheel and roller bearing 
such proportion as 2 is to 20 in diameter, and the handle 
and pinion bearing such proportion as 1 is to 10 in radius. 
Begin first with the weight and pulleys, and say if 6 pul- 
leys give 6000 lbs., 1 pulley or roller will give 1000 ; or 
set 6, the number of pulleys on B, to 6000, the number 
of pounds on A, and against 1 roller on B is 1000 on A, 
then say if 2, the inches diameter of the roller or axle 
give 1000, the number of pounds being on it, or the 
weight over the 6 pulleys, equal to 1000 lbs. then 20 
inches, the diameter of the wheel, will be equal to, or 
require 100 lbs. to balance it. 

Operation. Invert your slide and set 2 the diameter 
of the roller on C to 1000, the number of pounds on A, 
and against 20, the diameter of the wheel on C is 100 lbs. 



MECHANICAL EXERCISES. 303 

to balance the whole on A, then proceed with the han- 
dle and pinion, and say if 1 inch, the radius of the han- 
dle has 10 lbs. to lift. 

Operation. Set 1, the radius of the pinion on C to 
100, to the number of pounds to lift on A, and against 
10, the radius of the handle on C is 10 lbs. the first 
power applied on A, the answer sought. 

By this rule you may find any proportion of weight in 
any number of movements of any unequal proportion in 
any kind of mechanical powers, only observe where 
more requires more, or less requires less, then your slide 
must be the right way in, as usual, but when more re- 
quires less, and less requires more, then your slide must 
be inverted. 

Ex. 15. Required the velocity in inches per minute of 
the crane handle, while the weight 60001bs. passes through 
a space of 12.6 per minute. 

Ope^ration^. Set 6000, the number of pounds on C to 
12.6, the number of inches and parts that the weight 
raises on A, and against 10 lbs. the power applied on C 
is 75, 600 inches, the velocity per minute on A the 
answer. 

Ex. 16. Lever* Suppose a lever with 672 lbs. hung on 
the short arm 1 foot from the fulcrum or prop, required 
a weight to balance, hung at 6 feet from the fulcrum or 
prop, on the long arm, as 1 is to 672, so is 6 to the num- 
ber sought or answer; observe, it must be worked by 
inverse proportion. 

Operation. Invert your slide, and set 1 on C to 672 
on A, and against 6 on C is 112 lbs. the answer on A. 

Ex. 17. Wheel and Axle. Required a weight hung on 
the wheel 20 inches diameter to balance 100 lbs. hung on 
the axle 1 inch diameter. 

Operation. Invert your slide, set 1 on C to 100 on A, 
and against 20 on C is 5, the content on A. 

Ex. 18. Pulleys. Suppose 1000 lbs. to be hung at a 
pair of blocks, consisting of 10 pulleys, 5 loose, and 5 
fast, or 5 in the upper and 5 in the lower block, what 
weight should be hung at the last pulley to balance 



304 MECHANICAL EXERCISES. 

them? direct proportion, say as 10 pulleys or ropes are 
to 100 lbs., so is 1 rope or pulley to 10 lbs. the answer 
sought. 

Operation. Set 10 on B to 100 on A, and against 1 
on B is 10 the content on A. 

Ex. 19. Inclined Plane. Required a weight hung 
on the perpendicular height being 12 inches to balance 
75 lbs. hung on the slant height, being 36 inches. Direct 
proportion, say as 36, slant height is to 75 lbs. so is 12 the 
perpendicular height to the answer 25 lbs. 

Operation. Set 36 on B, to 75 on A, and against 12 
on B, is 25 the answer on A. 

Ex. 20. The Wedge. Required the power of a blow 
struck on a wedge, whose half thickness 1 inch, and 
length of one side 25 inches, and resistance 250 lbs. 

Operation. 25 on B, to 250 on A, and against 1 on B 
is 10, the answer on A. 

Ex. 21. The Screw. Required the resistance or weight 
lifted in pounds, the circumference of the screw being 
20 inches, the power applied being 100 lbs. and the dis- 
tance between two threads f of an inch. 

Operation. Invert your slide, and set 100 on C, to 
20 on A, and against 75, which is on f C, is 2650 the 
content on A. 

Ex. 22. The Engine Beam. Suppose the length of 
the beam from the centre to be 6 feet long, and length 
of stroke 4 feet long at the beam end, required the length 
of stroke, the same beam is making at 1|, 3 feet and 4^ 
ieei from the centre, or any other length of stroke within 
the same dimensions. 

Operation. Set 4, the length of stroke on B to 6, the 
length of the beam from the centre on A, and against 
1^, 3 and 4|^ feet on A is 1, 2, and 3 ieet, the content on 
B, or any other length that might be wanted within the 
same dimension. 

Ex. 23. Suppose the piston of a steam engine to travel 
220 feet per minute, and the length of stroke up and 
down to be 8 feet, what is the number of strokes per 
minute. 



MECHANICAL EXERCISES. 305 

Operation\ Set 8 on B to 1 on unity on A, and against 
220 on B is 27^, the content on A. 

Ex. 24. Suppose a piston to travel 220 feet per nnin- 
ute, and the number of strokes to be 27^ per minute, 
what is the length of one stroke up and down. 

Operatiokt. Set 27^ on A to 220 on B, against 1 on 
A, being 8 kety the length of stroke on B. 

Ex. 25. Required, the number of feet a piston travels 
in a minute, length of stroke being 8 feet, and number of 
strokes being 27^. 

Operation. Set 1 on A to 8 on B, and against 21^ on 
A, is 220 on B. 

Ex. 26. If a pendulum 39.2 inches long, make 60 vi- 
brations per minute, what will one of 12 inches long 
make. 

OpERATiopf. Invert your slide, and set 39.2 on B to 60 
on D, and against 12 on B, is 109, the content on D. 

Ex. 27. Required, the number of feet a stone will fall 
in 3 seconds, supposing it to fall 16 feet in the first 
second. 

Operatiokt. Set 1 on D to 16 on C, and against 3 on 
D, is 144 feet, the content on C. 

Ex. 28. Required, the circumference of a wheel, the 
diameter being 20 inches, 

Operation. Set 1 on B to 3.14 on A, and against 20 
on B, is 63, the content on A. 

Ex. 29. Required, the diameter of a wheel y the cir- 
cumference being 63 inches. 

Operation. Set 3.14, which is the circumference of 
1 inch on A, to 1, the diameter on B, and against 63, the 
circumference on A is 20, the diameter on B. By this 
rule, you find the pitch of all wheels nearly by setting 
the pitch of the cog on B to 3.14 on A, and against any 
diameter on B, is the number of cogs on A, or against 
any number of cogs on A, is the diameter on B. 

Ex. 30. Suppose a dr^um upon one shaft 20 inches 
diameter, to make 30 revolutions, which is turned by a 
first drum ; then required the diameter of the last drum, 
that makes 150 revolutions. 
26* 



306 MECHANICAL EXERCISES. 

Operation. Invert your slide, and set 30, the revolu- 
tions of the first drum on A to 20, the diameter of the 
first drum in C, and against 150, the revolution of the 
last drum on A is 4 inches, the diameter of the last drum 
on C. By this rule, you will find the revolution or diam- 
eter of any different speed of any number of drums of an 
unequal proportion ; for, as the revolutions on A are to 
the diameter on C, so is the diameter to the revolutions 
on A, or number sought. Observe, the slide must always 
be inverted in these operations. 

Ex. 31. Tiling and Slating. Required the number 
of Squares contained in a piece of tiling or slating 40 
feet long by 15 wide. 

Operation. Set 100 the number of feet in a square 
on A to 40 the length on B, and against 15, the width on 
A is 6, the content on B. 

Ex. 32. Required the number of roods contained in 
the above dimensions. 

Operation. Set 63, the number of ieet in a rood on 
A to 40, the length on B, against 15 on A is 9 J roods, 
the content on B. 

Ex. 33. Required the number of tiles sufficient to 
cover the above dimensions. 

Operation. Set 1 on A to 101|^, the tiles in a rood 
on B, and against 9|^ the roods on A is 965, the number 
of tiles required on B. 

Ex. 34. Painters* Work. Required the number of 
yards contained in a fence of 70 feet long, by 10^ feet 

high. 

Operation. Set 9, the number of ieei in a yard on 
A to 70 the length on B, and against lOi on A is 81f, 
the contents on B. 

Ex. 35. Glaziers' Work. Required the number of 
feet contained in a window 60 in. high, and 50 wide. 

Operation. Set 144, the number of superficial inch* 
es in a foot on A to 60, the length on B, and against 50, 
the width on A is nearly 21.0 feet, the content on B, or 
call it 5 feet high, and set 12 on A to 5 on B, and 
against 50 on A is nearly 21.0 k^ty the same as above 
on B. 



MECHANICAL EXERCISES. 307 

Ex. 36. Plasterers' Work. Required the number of 
yards contained in a piece of plastering, 42 feet long by 
18^ feet high. 

Operation^. Set 9 on A to 12, the length on B, and 
against SJ feet high is 39j yards nearly on B. 

Ex. 37. Pavers' Work. Required the number of 
yards contained in a piece of paving 16i ieei long by 
13| wide. 

Operation. Set 9 on A to 16^, the length on B, and 
against 13|- on A, are 35 yards, the content on B. 

Ex. 38. Required the number of bricks sutBcient for 
the above 25 yards, admitting the size of bricks to be 9 
by 4i inches, and a superficial yard to contain 32 bricks. 

Operation. Set 1 on A to 32 on B, and against 25 on 
A are 800 bricks, the content on B. 

Ex. 39. Digging. Required the number of solid yards 
contained in a piece of digging 15 feet long, 12 feet wide 
and 2 feet deep ; first find the mean proportion by setting 
15 on D to 15 on C, and against 12 on C is 13, 45, the 
square on D. 

Operation. Set 9 the depth on B to 17, the common 
divisor, on A, and against 13, 45 on D, are 60 yards, the 
content on C. 

Ex. 40. Timber Measure. Required the number of 
cubic kei contained in a piece of timber 22 feet long, and 
18 inches J girt. 

Operation. Set 22, the length on B to 9 the common 
divisor on A, and against the \ girt on D are 4.9\ feet, 
the content on C. 

Ex. 41. Required the product of 2f inches, multi* 
plied by 2f inches. ; ' 

Operation. Set 1 on A to 2J on B, and against 2f on 
A is 7.6, the content on B. 

Ex. 42. Required the number of Horse-power of a 
double powered Patent Steam Engine, the diameter of 
the cylinder being 24 inches. 

Operation. Set 5 on B to 9 on A, and against 24 on 
D is 20 the content on C ; observe, when the slide stands 
here, it is a table of diameters and horses'-power, D being 
a line of diameters, and C being a line of horses'-power. 



308 MECHANICAL EXERCISES* 

Ex. 43. Required the side of a square in inches, 
equal in area to a right angle triangle, whose base is 126 
inches, and perpendicular height 94 inches. 

Operation. Set 47, which is half the perpendicular 
on C to 47 the same on D, and against 126 on C is 76.9, 
the content on D; observe, taking half the perpendicular 
is the common rule in all triangles to find the area. 

Ex. 44. Required the side of a square in feet, equal 
in area to a common triangle, whose base is 48 feet, and 
perpendicular height 24 feet. 

Operation. Set 12, which is half the perpendicular 
on C to 12 the same on D, and against 48 on C is 24, the 
answer on D. 

Ex. 45. Required, the weight of a hay-stack, admit- 
ting 1 solid yard, or 27 solid feet, to 1 cwt. 1 qr. 6 lb., 
and the stack to measure 30 feet long, 12 feet wide, and 
10 feet high, up to the hips, or eaves. In this case, it will 
be necessary to take the length and width about 5 feet 
high, that is, about the middle, calling this the mean 
proportion, which will be suflficiently true in cases of 
this kind. 

Operation. The first thing is to find the square of it, 
which is necessary, in all unequal dimensions, before the 
question can be stated : this is found by setting 30, the 
feet long, on SO, the same on D, and against 12, the feet 
wide on C, are 19, the feet square on D nearly, then set 
10, the feet high on B, to this common number or divisor, 
136 on A, and against 19, the feet square on D, is 167 
cwt. qr. lb., the content on C. 

Ex. 46. Required, the content of the top of the stack 
(that is, that part above the hips or eaves, which con- 
tains the roof, &c.,) its length being 30 feet, width being 
12, and perpendicular height being 10 feet 

Operation. Set 5, which is half the perpendicular on 
B, that is, the depth to that common number or divisor 
136, as above, and against 19, the square on D, as in ex- 
ample above, is 83 cwt. 1 qr., the content on C Now, 
the body of the stack being 167 cwt. qr. lb., which 
being added to 83 cwt. 1 qr. lb., makes the whole 250 
cwt. 1 qr., the answer. 



MECHANICS. 



The science of mechanics has been very concisely de- 
fined the geometry of motion. It is divided, by Sir Isaac 
Newton, into the two branches of practical and rational 
mechanics. Practical mechanics treat of the six mechani- 
cal powers, of one or more of which every machine is 
composed ; and rational mechanics comprehends the 
whole theory of motion, shows how to determine the mo- 
tions produced by given powers or forces, and, conversely, 
when the phenomena of the motions are given, how to 
trace the power of forces from which they arise. 

To enter into a full detail of mechanics, would swell 
this volume beyond its intended limits; and, having 
dwelt somewhat at large on mechanical exercises, under 
this head, we shall only add an Abstract of Mechanics. 

ABSTRACT OF MECHANICS. 

OF MATTER. 

1. Every portion of matter is possessed of the follow- 
ing properties, viz. solidity, extension, divisibility, mobility, 
inertia, attraction, and repulsion. 

2. Solidity is that property by which two bodies can- 
not occupy the same place at the same time. It is some- 
times called the impenetrability of matter. 

3. The extension^ like the solidity of matter, is proved 
by the impossibility of two bodies co-existing in the same 
place. 

4. Divisibility is that property by which bodies are 
capable of being divided into parts removeable from each 
other. 

5. Mobility expresses the capacity of matter to be 
iDOved from one position or part of space to another. 

(309) 



310 ABSTRACT OF MECHANICS. 

6. Inertia is the term which designates the passiveness 
of matter, which, if at rest, will for ever remain in that 
state, until compelled by some cause to move ; and, on 
the contrary, if in motion, that motion will not cease, or 
abate, or change its direction, unless the body be resisted. 

I SPACE. 

1. Space is either absolute or relative. 

2. Absolute space is merely extension, illimitable, im- 
moveable, and without parts ; yet, for the convenience 
of language, it is usually spoken of as if it had parts. 
Hence the expression, 

3. Relative space, which signifies that part of absolute 
space which is occupied by any body, as compared with 
any part occupied by another body. 

ATTRACTION. 

1. Attraction denotes the property which bodies have 
to approach each other. 

2. There are five kinds of attraction, the attraction 
of cohesion, of gravitation, of electricity, of magnetism, 
and chemical attraction. 

3. The attraction of cohesion is exerted only at very 
small distances. 

4. The strength of the attraction of cohesion being 
different in different kinds of matter, is supposed to be 
the cause of the relative degrees of hardness of different 
bodies. 

5. Capillary attraction is only a particular modification 
or branch of the attraction of cohesion. 

6. The attraction of gravitation is exerted by every 
particle of matter on every other particle at all distances, 
but by no means with equal intensity at all distances. 

7. Gravitation decreases from the surface of the earth 
upwards as the square of the distance increases ; but 
from the surface of the earth downwards, it decreases 
only in a direct ratio to the distance from the centre. 



ABSTRACT OF IVIECHANICS. 311 

REPULSION. 

1. Repulsion is that property in bodies, whereby, if 
they are placed just beyond the sphere of each other's 
attraction of cohesion, they mutually fly from each other. 

2. Oil refuses to mix with water, from the repulsion 
between the particles of the two substances ; and from 
the same cause, a needle gently laid upon water will swim. 

MOTION. 

1. Absolute motion is the actual motion that bodies 
have, considered independently of each other, and only 
with regard to the parts of space. 

2. Relative motion is the degree and direction of the 
motion of one body, when compared with that of another. 

3. Accelerated motion is when the velocity continually 
increases. 

4. Retarded motion is when the velocity continually 
decreases ; and the motion is said to be uniformly re^ 
tarded, when it decreases equally in equal times. 

5. The velocity of uniform motion is estimated by the 
time employed in moving over a certain space ; or, which 
amounts to the same thing, by the space moved over in a 
certain time. 

6. To ascertain the velocity, divide the space run over 
by the time. 

7. To ascertain the space nm over, multiply the veloci- 
ty by the time. 

8. In accelerated motion, the space run over is as the 
square of the time, instead of being directly as the time, 
as in uniform motion. 

9. A body acted upon by only one force, will always 
move in a straight line. 

10. Bodies acted upon by two single impulses, whether 
equal or unequal, will also describe a right line. 

11. But when a body is acted upon by one uniform 
force, or single impulse, and another accelerated or re- 
tarded force, the two forces will cause it to describe a 
curve. 



312 ABSTRACT OP MECHANICS. 

12. The curve described by a body projected from the 
earth, and drawn down by the action of gravity, would, 
in an unresisting medium, be that of a parabola ; but 
from the resistance of the air, which, when the velocity 
is very great, will often amount to one hundred times 
the weight of the projectile, the curve really described! 
approaches more nearly to that of a hyperbola. 

13. The momentum of a body is the force with which 
it moves, and is in proportion to the weight, or quantity 
of matter, multiplied into its velocity. 

14. The actions of bodies on each other are always- 
equal, and exert in opposite directions ; so that any body 
acting upon another, loses as much force as it commu- 
nicates. 

CENTRAL FORCES. 

1. The central forces are the centrifugal and the 
centripetal forces. 

2. The centrifugal force is the tendency which bodies 
that revolve round a centre, have to fly from it in ai 
tangent to the curve they move in, as a stone from ai 
sling. 

The centripetal force is that which prevents a body 
from flying off, by impelling it towards the centre, as the 
attraction of gravitation. 

CENTRE OF GRAVITY. 

1. The centre of gravity is that point in a body about 
which all its parts exactly balance each other in every 
position. - 

2. A vertical line passing through the centre of gra- 
vity of a body, is called the line of direction. 

3. When the line of direction falls within the base of 
a body, that body cannot descend ; but if it falls without 
the base, the body will fall. 

THE LEVER. 

1. There are three kinds of levers, the difference 
between which is constituted by the difference in the 



ABSTRACT OF MECHANICS. 313 

situation of the fulcrum, and the power with respect to 
each other. In the first kind of lever, the fulcrum is 
placed between the power and the weight. In the second 
kind of lever, the fulcrum is at one end, the power at 
the other, and the weight between them. In the third 
kind of lever, the power is applied between the fulcrum 
and the weight. 

2. In all these levers, the power is to the weight, as 
the distance of the weight from the fulcrum is to that 
of the power from the fulcrum. 

3. A hent or hammer lever, differs only in the form 
from a lever of the first kind. 

4. Scissors, pincers, snuffers, and the common iron- 
screw, are all levers of the first kind. 

5. The strutera or Roman steel-yard, is a lever of the 
first kind, with a moveable weight. 

6. A balance is also a lever of the first kind with 
equal arms ; a perfect balance should combine the fol- 
lowing requisites. 1. The arms of the beam should be 
exactly equal, both as to weight and length, and should 
at the same time be as long as possible, relatively to 
their thickness. 2. The points from which the scales are 
suspended, should be in a right line, passing through the 
centre of gravity of the beam. 3. The fulcrum ought 
to be a little higher than the centre of gravity. 4. The 
axis of motion should be formed with an edge like a 
knife, and, with the rings and other bearing parts, should 
be very hard and smooth. 5. The pivots, which form 
the axis of motion, should be in a straight line, and at 
right angles to the beam. 

7. The best balances are not calculated to determine 
weights with certainty to more than five places of 
figures. 

8. The oars and rudders of vessels are levers of the 
second order ; a pair of bellows, nut-crackers, &c. are 
composed of two levers of the same kind. 

9. The third kind of lever is used as little as possible, 
on account of the disadvantage to the moving power, the 
intensity of which must always exceed the resistance ; 

27 



314 ABSTRACT OF MECHANICS. 

yet in some cases this disadvantage is over-balanced by 
the quickness of its operations, and the snnall compass in 
which it is exerted ; hence its fitness for the bones of the 
arm, and the limbs of animals generally. 

10. In compound levers, the power is to the weight, in 
a ratio compounded of the several ratios which those 
powers that can sustain the weight by the half of each 
lever, when used singly and apart from the rest, have to 
the weight. 

THE PULLEY. 

1. Pulleys are of two kinds, jf?a:e6? and moveable. 

2. The fixed pulley only turns upon its axis, and aflfords 
no mechanical advantage; therefore, when the power 
and the weight are equal, they balance each other. It 
is used for the convenience of changing the direction of a 
motion. 

3. The moveable pulley not only turns upon its axis, but 
rises and falls with the weight. 

4. Every moveable pulley may be considered as hang- 
ing by two ropes equally stretched, and which, conse- 
quently, being equal portions of the weight, therefore 
each pulley of this sort doubles the power. 

5. A pulley of one spiral groove upon a truncated cone, 
as the fusee of a watch, is calculated to maintain a con- 
stant equilibrium or relation between two powers, the 
relative forces of which are continually changing. 

WHEEL AND AXLE. 

1. The power must be to the weight, in order to pro- 
duce an equilibrium, as the circumference of the wheel is 
to the circumference of the axle. 

2. As the diameters of different circles bear the same 
proportion to each other that their respective circum- 
ferences do, the power is also to the weight as the diam- 
eter of the wheel to the diameter of the axle. 

3. If one wheel move another of equal circumference, 
no power will be gained, as they will both move equally 
fast 



ABSTRACT OF MECHANICS* 315 

4. But if one wheel move another of different diame- 
ter, whether larger or smaller, the velocities with which 
they move will be inversely as their diameters, circum- 
ferences, or number of teeth. 

5. The wheel and axle may be considered as a per- 
petual lever, from the constant renewal of the points of 
suspension and resistance. The fulcrum is the centre of 
the axis, the longer arm is the radius of the wheel, and 
the shorter arm the radius of the axis. 

6. The crane, and many other machines, of the first 
consequence, are composed principally of the wheel and 
axle. 

THE INCLINED PLANE. 

1. The power and the weight balance each other, 
when the former is to the latter as the height of the 
plane to its length. 

2. In estimating the draught of a wagon, or other 
vehicle, up-hill, the draught on the level must be added ; 
so that, if the hill rises one foot in four, one fourth part 
of the weight must be added to the draught on level 
ground. 

THE WEDGE. 

1. When the resistance acts perpendicularly to the 
sides, that is, when the wedge does not cleave at any 
distance, there is an equilibrium between the resistance 
and the power, when the latter is to the former as half 
the thickness of the back of the w^edge is to the length 
of one of its sides. 

2. When the resistance on each side acts parallel to 
the back, that is, when the wedge cleaves at some dis- 
tance, the power is to the resistance as the whole length 
of the back to double its perpendicular height. 

3. The thinner the wedge, the greater its power. 

4. The further a wedge is driven into any material, 
the greater also is its power, the sides of the cleft afford- 
ing it the advantage of operating upon two levers. 

5. Axes, spades, chisels, knives, and all instruments 



316 ABSTRACT OF MECHANICS. 

which begin with edges or points, and grow gradually 
thicker, act on the principle of the wedge. 

THE SCREW. 

1. The screw is an inclined plane encompassing the 
cylinder. 

2. It is generally used with a lever ; and the power is 
to the weight, as the distance from one thread or spiral 
to another is to the circumference of the circle described 
by the power. 

3. The friction of the screw is very great, a circum- 
stance that occasions this machine to sustain a weight or 
press upon a body, after the power by which it was 
impelled is removed. 

4. A screw cut on an axle to serve as a pinion, is 
called an endless screw. 

5. The endless screw is very useful, either in converting 
a very rapid motion into a slow one, or vice versa, as for 
each of its revolutions the wheel moves but one- tenth. 

COMPOUND MACHINES. 

1. In all machines, simple as well as compound, what 
is gained in power is lost in time ; but the loss of time is 
compensated by convenience. 

2. The mechanical power of an engine may be known 
by measuring the space described in the same time by 
the power and the resistance or weight ; or by multiply- 
ing into each other the several proportions subsisting 
between the power and the weight, in every simple me- 
chanical power of which it is composed. 

3. The power of a machine is not altered by varying 
the size of the wheels, provided the proportion produced 
by the multiplication of the power of the several parts 
remains the same. 

4. In constructing machines, simplicity of parts and 
uniformity of motion should be particularly studied. 

5. The teeth of wheels should always be made as 
numerous as possible; and when great strength is re- 
quired, it should be obtained by increasing the width or 
thickness of the wheel. 



ABSTRACT OF MECHANICS. 317 

6. The use of the crank is one of the best modes of 
converting a reciprocating into a rotatory motion, and 
vice versa. 

FLY-WHEELS. 

1. A fly-wheel is a reservoir of power, and is employed 
to equalize the motion of a machine. 

2. This equalization of the motion is the only source 
of the advantage of a fly, which can impart no power it 
has not received. 

3. When a fly is used merely as a regulator, it should 
be near the first mover; if intended to accumulate force 
in the working point, it should not be separated far from 
that point. 

FRICTION. 

1. Friction is occasioned by the roughness and cohe- 
sion of bodies. 

2. It is in general equal to between one-half and one- 
fourth of the weight or force with which bodies are 
pressed together. 

3. It is increased in a small degree by an increase of 
the surfaces in contact. 

4. It is increased to an extraordinary degree, by pro- 
longing the time of contact. 

5. Two metals of the same kind have more friction 
than two different metals. 

6. Steel and brass are the two metals which have the 
least friction upon each other. 

7. The general rule for lessening friction consists in 
substituting the rolling for the sliding motion. 

MEN AND HORSES, CONSIDERED AS FIRST 
MOVERS, 

1. In turning a wrench, .a man exerts his strength in 
different proportions at different parts of the circle. The 
force is^ when he pulls the handle up froui the height of 
his knee ; and the least when he thrusts from him hori- 
zontally. 

27* 



318 ABSTRACT OF MECHANICS. 

2. When two handles are used to an axle, one at each 
extremity, they should be fixed at right angles to each 
other. 

3. The art of carrying lar^e burdens, consists in keep- 
ing the column of the body as directly under the weight 
and as upright as possible. 

4. The horse exerts his force to the greatest advan- 
tage in dravi^ing or carrying up a hill. 

5. The force with which a horse works, is compounded 
of his w^eight and muscular strength. 

6. The walk of a horse working in a mill should never 
be less than forty feet in diameter. 

! 7. A horse exerts most strength when drawing upon a 
plane. 

MILL-WORK. 

1. Water-wheels are of three kinds ; viz. undershot- 
wheels, breast-wheels, and overshot- wheels. The powers 
necessary to produce the same effect on each of these 
must be to each as the numbers 2.4, L75, and L 

2. The undershot-wheel is used only w^hen a fall-water 
cannot be obtained. 

3. A water-wheel twice as broad as another has more 
than double the force. 

4. An axis, furnished with a very oblique spiral, and 
placed in the direction of a stream, may be rendered a 
powerful first-mover, adapted to a deep and slow current 

5. A mill-stone should make 120 revolutions in a 
minute. 

6. Bevelled'Wheels are much used for changing the 
direction of motion in wheel work. 

7. Hooke's universal joint is sometimes used with ad- 
vantage for the same purpose. 

8. The teeth of wheels should never, if it can be 
avoided, act upon each other before they arrive at the 
line joining the centres. 

9. To ensure a uniformity of pressure and velocity in 
the action of one wheel upon another, the teeth should 
l>e formed into epicycloides, or into involutes, of the cir- 



ABSTRACT OF MECHANICS. 319 

curnferences of the respective wheels ; or if the teeth of 
one wheel be either circular or triangular, the teeth of 
the same wheel should have a figure compounded of an 
epicycloid, and that of the figure of the firist wheel. 

10. The object of thus forming the teeth is, that they 
may not slide^ but roll upon each other ; by which means, 
the friction is almost annihilated. 

11. It is a great improvement in machinery, where 
trundles are employed Vv-ith cylindrical staves, to make 
these staves moveable on their axis. 

12. A heavy mill-stone requires very little more power 
than a light one ; but it performs much more work, and 
more effectually equalizes the motion, like a heavy fly. 

13. The corn as it is ground, is thrown out between 
the mill-stones, by the centrifugal force it has acquired. 

14. The manual labour of putting the ground corn into 
sacks, in order to raise it to the top of a mill-house, may 
be obviated by the use of a chain of buckets wrought 
by machinery. 

WHEEL CAPvRIAGES. 

1. A HORSE draws with the greatest advantage, when 
the line of traction or draught is inclined upwards, so as 
to make an angle of about 15 degrees with the horizon- 
tal plane. 

2. By this inclination, the line of traction is set at 
right angles to the shape of the horses' shoulders, all 
parts of which are, therefore, equally pressed by the 
collar. 

3. Single horses are preferable to teams, because in a 
team, all but the shaft horse draw horizontally, and con- 
sequently to disadvantage. 

4. A horse, when part of the weight presses on his 
back, will draw a weight to which he w^ould otherwise 
be incompetent. 

5. The fore-wheels of carriages are less than the hind- 
wheels, for the convenience of turning in a smaller com- 
pass. 

6. In ascending, high wheels facilitate the draught, in 



320 ABSTRACT OF MECHANICS. 

proportioa to the squares of their diameters; but in 
descending, they press in the same proportion. 

7. In descending, the body of a cart may be advan- 
tageously thrown backwards, so that the bottom of it 
will be horizontal, while the shafts incline downwards. 

8. In loading four-wheeled carriages, the greatest 
weight should be laid upon the large wheels. 

9. Dished wheels are better calculated than any other 
to sustain the jolts and unavoidable inequalities of pres- 
sure arising from the roughness of roads. 

10. The extremities of the axles should be in the same 
horizontal plane, and the wheels should be placed on 
them at right angles. 

11. Broad cylindrical wheels smooth and harden a 
road, while narrow ones cut it into furrows, and conical 
ones grind the hardest stones to powder. 

CLOCK-WORK. 

1. To ascertain the number of revolutions which a 
pinion makes, for one of the wheels working in it, divide 
the number of its leaves by the number of teeth of the 
wheel, and the answer is obtained. 

2. By increasing the number of teeth in the wheels ; 
by diminishing the number of leaves in the pinions ; by 
increasing the length of the cord that suspends the 
weight ; and lastly, by adding to the number of wheels 
and pinions, a clock may be made to go any length of 
time, as a month, or a year, without winding up. 

3. The inconvenience of taking up more room, but 
principally the increase of friction which would be in- 
troduced, are the causes of its being inexpedient to 
make a cbck go beyond eight days. 

4. Clocks intended to keep exact time, are contrived 
to go whilst winding up. 

5. Clocks which have pendulums vibrating half se- 
conds, are frequently moved by a spring instead of a 
weight. 

6. A spring is strongest when it is first wound up, and 
gradually decreases in strength till the movement stops ; 



ABSTRACT OF MECHANICS. 321 

it is therefore contrived to draw the chain over a conical 
barrel, so that the lev^er at which it pulls is lengthened 
as it grows weaker, by which means its effects are 
equalized. 

7. The plates of clock-makers' engines may be quick- 
ly divided into odd numbers, by subtracting from the odd 
number so much as will leave an even number of easy 
subdivision ; then calculating the number of degrees con- 
tained in the parts subtracted, and setting them off on 
the circumference of the circle from a sector. 

8. The geometrical radius of wheels, when the teeth 
are epicycloidal, is less than the acting diameter, by 
about f ths of the breadth of a teeth or measure. 

9. The relative size of a pinion must be less for a 
small wheel than for a large one, and also smaller when 
driven than when it is the driver. 

PENDULUMS. 

1. All vibrations of the same pendulum, whether 
great or small, if cycloidal, are performed in equal times. 

2. The longer a pendulum, the slower are its vibra- 
tions. 

3. A pendulum to vibrate seconds, must be shorter at 
the equator than at the poles. 

4. Heat lengthens and cold shortens pendulums. 

5. The quicksilver pendulum, the gridiron pendulum, 
and many others, have been contrived to obviate these 
effects of the change of temperature. 

6. The vibrations of pendulums are affected by differ- 
ences in the density of the medium in which they are 
performed. 

7. The merit of the only contrivance to remedy this 
defect is due to Rittenhouse. It consists in the use of 
two pendulums, one of which is very light, and placed 
in an inverted position, extending above the point of sus- 
pension of the other. 

8. This compound pendulum may be made to vibrate 
quicker in so dense a medium as water than in the open 
air. 



GENERAL AND MOST USEFUL SELECTION 



RECEIPTS: 

WHICH WILL PROVE OP THE GREATEST UTILITY 

TO 

THE ARTIST, THE MECHANIC, 
THE FARMER, AND THE LABOURING MAN. 

EMBRACING 

THE WHOLE COURSE OF THE ARTS, 

Selecting and reducing such parts as are often wanted, when the employment 
of the professors of such businesses would be too expensive and embar- 
rassing. The aid of which will enable also the experimenter 
impelled by genius to perform and invent with greater 
ease and success, in some cases ; while in others 
obstacles will be removed that otherwise 
would be insurmountable. 

(323) 



i 



MISCELLANEOUS RECEIPTS. 



Method for making Black Writing-Ink. 

^ In six quarts of water, boil four ounces of logwood in 
chips, cut very thin across the grain. The boiling may 
be continued for nearly an hour, adding, from time to 
time, a little boiling water, to compensate the waste by 
evaporation. Strain the liquor while hot, suffer it to 
cool, and make up the quantity equal to tive quarts, by 
the further addition of cold water. To this decoction, put 

1 lb. avoirdupois of blue galls, coarsely bruised; or 
20 oz. of the best galis, in sorts. 
4 oz. of sulphate of iron, calcined to whiteness. 
^ oz. of acetate of copper, previously mixed with the 

decoction till it forms a smooth paste. 
3 oz. of coarse sugar, and 
6 oz. of gum-Senegal or Arabic. 

These several ingredients may be introduced one after 
another, contrary to the advice of some, who recommend 
the gum, &c. to be added when the ink is nearly made. 
The composition produces the ink usually called Japan 
Ink, from the high gloss which it exhibits when written 
w^ith ; and a small phial of it has been sold for 12 cents. 

The above ink, though possessing the full proportion 
of every ingredient known to contribute to the perfection 
of ink, will not cost more, to those who prepare it for 
themselves, than the commonest ink which can be bought 
by retail. The receipt was given to the public by De- 
sormeaux. It answers for copying letters, by transferring 
from them an impression to a damp sheet of thin, unsized 
paper, passing through a small rolling-press. 

When gum is very dear, or when no very high gloss 
28 Cii^^} 



326 MISCELLANEOUS RECEIPTS. 

is required, four ounces will be sufficient, with one ounce 
and a-half of sugar. 

By using only 12 oz. of galls to 4 oz. of sulphate of iron, 
uncalcined, omitting the logwood, and acetate of copper, 
and the sugar, and using only 3 oz. of gum, a good and 
cheap common ink will be obtained. 

Lamp-black has been added to ink, to prevent its col- 
our from being destroyed by the action of the oxy-mu- 
riatic acid. It should be burnt in a closed crucible, to 
render it less oily. It causes the ink to write much 
less freely, although it may be useful for particular oc- 
casions. 

Red' Ink for Writing. 

Boil over a slow fire, 4 oz. of Brazil-wood, rn small 
raspings or chips, in a quart of water, till a third part of 
the water is evaporated. Add during the boiling, two 
drams of alum in powder. When the ink is cold, steam 
it through a fine cloth. Vinegar or stale urine is often 
used instead of water. In case of using water, I pre- 
sume a very small quantity of sal-ammoniac would im- 
prove this ink. 

Blue- Ink. 

Take Sulphate of Indigo, dilute it with water till it 
produces the colour required. It is with sulphate very 
largely diluted, that the faint blue lines of ledgers and 
other account books are ruled. If the ink were used 
strong, it would be necessary to add chalk to it, to neu- 
tralize the acid. The sulphate of indigo may be had of 
the woollen dyers. 

Fire and Water-proof Cement. 

' To half a pint of milk, put an equal quantity of vine- 
gar, in order to curdle it ; then separate the curd from 
the whey, and mix the whey with four or five eggs, 
beating the whole well together. When it is well mixed, 
add a little quicklime through a sieve, until it has ac- 
quired the consistence of a thick paste. With this 



MISCELLANEOUS RECEIPTS. 327 

cement, broken vessels and cracks of all kinds may be 
mended. It dries quickly, and resists the action of water, 
as well as of a considerable degree of fire. 

J Cement for stopping the Fissures of Iron Vessels. 

Take two ounces of muriate of ammonia, one ounce 
of flowers of sulphur, and sixteen ounces of cast-iron 
filings or turnings ; mix them well in a mortar, and keep 
the powder dry. When the cement is wanted, take one 
part of this and twenty parts of clean iron filings or 
borings, grind them together in a mortar, mix them with 
water to a proper consistence, and apply them between 
the joints. 

This answers for flanges of pipes, &c. about steam 
engines. 

Lutes. 

Lutes are compositions which are employed to defend 
glass and other vessels from the action of fire, or to fill 
up the vacancies which occur, when separate tubes, for 
the necks of different vessels, are inserted into each other 
during the process of distillation. Those lutes which 
are exposed to the action of fire, are usually called fii^e 
lutes. 

For a very excellent fire-lute, which will enable glass 
vessels to sustain an incredible degree of heat, take frag- 
ments of porcelain, pulverize and sift them well, and add 
an equal quantity of fine clay, previously softened with 
as much of a saturated solution of muriate of soda, 
as is requisite to give the whole a proper consistence. 
Apply a thin and uniform coat of this composition to the 
glass vessels, and allow it to dry slowly before they are 
put into the fire. 

Equal parts of coarse and refractory clay mixed with 
a little hair, form a good lute. 

Fat earth, beaten up with fresh horse-dung, Chaptal 
recommends as an excellent fire-lute, which he generally 
used, and the adhesion of which was such, that after the 
retort had cracked, the distillation could be carried on 
and regularly finished. 



328 MISCELLANEOUS RECEIPTS. 

Lutes for the joining of such vessels as retorts and re- 
ceivers, are varied according to the nature of the vapours 
which will act against them, in order not to ennploy a 
more expensive and troublesome composition than the 
case requires. For resisting watery vapours, slips of wet 
bladder, or slips of wet paper or linen, covered with stiff 
flour paste, may be bound over the juncture. 

A closer and neater lute for more penetrating vapours, 
is composed of whites of eggs made into a smooth paste 
with quick-lime, and applied upon strips of linen. The 
quick-lime should be previously slacked in the air, and 
reduced to a fine povvder. The cement should be ap- 
plied the moment it is made ; it soon dries, becomes very 
firm ; and is in chemical experiments one of the most 
useful cements known. 

Where saline, acrid vapours are to be resisted, a 
lute should be composed of boiled linseed oil intimately 
mixed with clay, which has been previously dried, finely 
powdered, and sifted. This is called fat lute. It is ap- 
plied to the junctures, as the undermost layers, and is 
secured in its place by the white of egg-lute last mention- 
ed, which is tied on with pack-thread* 

Blacking, to make. 

Pax 1 gallon of vinegar into a stone jug, add 1 lb. of 
ivory-black, well pulverized, ^ a lb. of loaf sugar, ^ an 
oz. of oil of vitriol, and 1 oz. of svi^eet oil; incorporate the 
whole by stirring. 

This is a blacking of very great repute in different 
countries, and on which great praise has been very de- 
servedly bestowed. It has decidedly been ascertained, 
from experience, to be less injurious to the leather, than 
most public blackings ; and it certainly produces a fine 
jet polish, which is rarely equalled, and never yet sur- 
passed. 



MISCELLANEOUS RECEIPTS. 329 



; VARNISHES 

To dissolve Copal in Alcohol. 

G)PAL, which is called gum copal, but which is not, 
strictly, either a gum or a resin, is the hardest and least 
changeable of all substances adapted to form varnishes, 
by their dissolution in spirit, or essential, or fat oils. It, 
therefore, forms the most valuable varnishes ; though we 
shall give several receipts where it is not employed, 
which form cheaper varnishes, sufficiently good for many 
purposes, adding only the general rule, that no varnish 
must be expected to be harder than the substance from 
which it is made. 

To dissolve copal in alcohol, dissolve half an ounce of 
camphor in a pint of alcohol; put it into a circulating 
glass, and add 4 oz. of copal in small pieces ; set it in a 
sand-heat, so regulated that the bubbles may be counted 
as they rise from the bottom, and continue the same heat 
till the solution is completed. 

The process above-mentioned will dissolve more copal 
than the menstruum will retain when cold. The most 
economical method will therefore be, to set the vessel 
which contains the solution by for a few days, and, when 
it is perfectly settled, pour off the clear varnish, and leave 
the residue for future operation. 

The solution of copal thus obtained is very bright. It 
is an excellent varnish for pictures, and would, doubtless, 
be an improvement in japanning, where the stoves used 
for drying the varnished articles would drive off the 
camphor, and leave the copal clear and colourless in the 
work. 

To dissolve Copal in Spirits of Turpentine, 

Reduce 2 oz. of copal to small pieces, and put them 
into a proper vessel. Mix a pint of the best spirits of 
turpentine with one eighth of spirits of sal ammoniac ; 
shake them well together, put them to the copal, cork 

28* 



330 MISCELLANEOUS RECEIPTS. 

the glass, and tie it over with a string or wire, making a 
small hole through the cork. Set the glass in a sand- 
heat so regulated as to make the contents boil as quickly 
as possible, but so gently that the bubbles may be counted 
as they rise from the bottom. The same heat must be 
kept up exactly till the solution is complete. 

It requires the most accurate attention to succeed in 
this operation. After the spirits are mixed, they should 
be put to the copal, and the necessary degree of heat be 
given as soon as possible, and maintained with the utmost 
regularity. If the heat abates, or the spirits boil quicker 
than is directed, the solution will immediately stop, and 
it will afterwards be in vain to proceed with the same 
materials ; but if properly managed the spirit of sal 
ammoniac will be seen gradually to descend from the 
mixture, and attack the copal, w^hich swells and dissolves, 
excepting a very small quantity which remains undis- 
solved. 

It is of much consequence that the vessel should not 
be opened till some time after it has been perfectly cold ; 
for if it contain the least warmth when opened, the whole 
contents will be blown out of the vessel. 

Whatever quantity is to be dissolved, should be put 
into a glass vessel capable at least of containing four 
times as much, and it should be high in proportion to the 
width. 

This varnish is of a deep rich colour, when viewed in 
the bottlii, but seems to give no colour to the pictures 
upon which it is laid. If it be left in the damp, it re- 
mains racky, as it is called, a long time ; but if kept in 
a warm room, or placed in the sun, it dries as well as 
any other turpentine varnish, and when dry it appears 
to be as durable as any other solution of copal. 

Copal may also be dissolved in spirits of turpentine by 
the assistance of camphor. 

Turpentine varnishes dry more slowly than those made 
with alcohol, and are less hard ; but they are not so li^i- 
ble to crack. 
ikoo ,1 



MISCELLANEOUS ftECEIPTS. 331 

To dissolve Copal in fixed- Oil. 

Melt, in a perfectly clean vessel, by a very slow heat, 
one pound of clear copal ; to this, add from one to two 
quarts of drying linseed oil. When these ingredients are 
thoroughly mixed, remove the vessel from the fire, and 
keep constantly stirring it, till nearly cold ; then add a 
pound of spirits of turpentine. Strain the varnish through 
a piece of cloth, and keep it for use. The older it is, the 
more drying it becomes- 

This varnish is very proper for wood-work, house and 
carriage painting. 

Seed'lac Varnish* 

Take three ounces of seed-lac, and put it, with a pint 
of spirits of wine, into a bottle, of which it will not fill 
more than two-thirds. Shake the mixture well together, 
and place it in a gentle heat, till the seed-lac appears 
to be dissolved : the solution will be hastened by shaking 
the bottle occasionally. After it has stood some time, pour 
oif the clear part, and keep it for use in a well-stopped 
bottle. The seed-lac should be purified before it is used, 
by washing it in cold water, and it should be in coarse 
powder, when added to the spirit. 

This varnish is next to that of copal in hardness, and 
has a reddish-yellow colour : it is, therefore, only to be' 
used where a tiqge of that kind is not injurious, 

Shell'lac Varnish, 

Take live oz. of the best shell-lac, reduce it to a gross 
powder, and put it into a bottle in a gentle heat, or a 
warm, close apartment, where it must continue two or 
three days, but should be frequently well shaken. The 
lac will then be dissolved, and the solution should then 
be filtered through a flannel bag ; and, when the portion 
that. will pass through freely is cooie off, it should be kept 
for use in well-stopped bottles. 

The portion which can only be made to pass through 
the bag by pressure, may be reserved for coarse purposes. 



332 MISCELLANEOUS RECEIPTS. 

Shell-lac varnish is rather softer than seed-lac varnish, 
but it is the best of varnishes for mixing with colours to 
paint with, instead of oil, from its working and spreading 
better in the pencil. 

Varnish for Toys, Silvered Clock-faces, and Furniture, 
not exposed to hardship. 

Dissolve two ounces of gum-mastic, and eight ounces 
of gum-sandrach, in a quart of alcohol ; then add four 
ounces of Venice turpentine. The addition of a little of 
the whitest part of gum-benjamin will render the varnish 
less liable to crack. 

Anther Varnish. 

Amber forms a very excellent varnish : its solution 
may be effected by boiling it in drying linseed oil. 

Oil- varnishes, which have become thick by keeping, 
are made thinner with spirits of turpentine. 

A Varnish for Copper-plate Prints. 

Prepare water by dissolving in it some isinglass ; lay 
on, with a soft brush, a coat of this. Let dry. Put on 
another, if necessary. Let dry. Then lay on another, 
of the following varnish. — True French spirit of wine, 
half a pound ; gum-elemi, two drachms, and sandarach, 
three. 

A curious and easy Varnish to engrave with aquafortis. 

Lay on a copper-plate as smooth and equal a coat as 
possible, of linseed oil. Set the plate on a gentle heat, 
that the oil may congeal, and dry itself in. When you 
find it has acquired the consistence of a varnish, tFien 
you may draw with a steel point, in order to etch your 
copper, and put on the aquafortis afterwards. 

A Varnish to gild with, without Gold. 

Take half a pint of spirits of wine, in which you dis- 
solve one drachm of saffron, and half a drachm of dra- 



MISCELLANEOUS RECEIPTS. 333 

gon*s blood, both previously well pulverized together. 
Add this to a certain quantity of shell-lac varnish, and set 
it on the fire with two drachnns of soccotrine aloes. 

Japanning. y 

Japanning is the art of varnishing in colours, and is 
frequently combined with painting. 

The substances proper for japanning, are wood, nnetal, 
with all others which retain a determinate form, and are 
capable of sustaining the operation of drying the var- 
nish. Paper and leather, therefore, when wrought into 
forms in which they remain stretched, stiff, and inflexible, 
are very common subjects for japanning. 

The article to be japanned is first rendered smooth 
and perfectly clean, it is then brushed over with two or 
three coats of seed-lac varnish, (see under the head of 
varnishes) except that the coarsest varnish will answer 
the purpose. The varnish thus laid on is called the 
priming. The next operation is to varnish the article 
again with the best varnish previously mixed with a pig- 
ment of the tint desired. This is called the grounding ; 
if the subject is to exhibit any painting, the objects are 
painted upon it, in colours mixed up with varnish, and 
used in the same manner as for oil-painting. The whole 
is then covered with additional coats of transparent 
varnish, and all that remains to be done, is to dry and 
polish it. 

Japanning should always be executed in warm apart- 
ments, as cold and moisture are alike injurious; and all 
the articles should be warmed before any varnish is ap- 
plied to them. One coat of varnish, also, must be dry 
before another is laid on. Ovens are employed to hasten 
the perfect drying of the v^^ork. 

AH the coloured pigments employed in oil or water, 
answer perfectly v^^ell in varnish, combined with which 
vehicle, many of those which fly in oil are perfectly 
unchangeable. The manner in which the colours are 
mixed with the varnish is extremely simple and easy ; 
they are first reduced, by the usual means of washing 



334 MISCELLANEOUS RECEIPTS. 

and levigation, to the finest state possible ; and the var- 
nish being contained in a bottle, they are added to it, till 
the requisite body of colour is obtained, the mixture 
being rendered connplete by stirring or shaking the bottle. 
When a single colour is intended, the varnish employed 
is of no consequence, if it be hard enough for the work, 
and not possessed of any colour inconsistent with the tint 
required ; but for painting with, shell-lac varnish is the 
best, and easiest to work : it is, therefore, employed in 
all cases where its colour permits, and for the lightest 
colours, mastic varnish is employed, unless the fineness 
of the work admits the use of copal dissolved in spirits 
of wine. lomcrfo: 

To spare varnish, the priming may be Composed of 
size mixed with whiting, to give it a body, as some sub- 
stances require mucl* varnish to saturate them ; but 
work primed with size is never durable ; it is liable to 
crack and fly off with the least violence, which never 
happens to work into v/hich the varnish can sink. Var- 
nish cannot sink into metals, and this is the reason that 
japanned metaK for example a japanned tin-plate tray, is 
of less value than a paper one. The battering which 
this piece of furniture sustains in its use, soon separates 
the japan from it in flakes, or scales ; which never hap- 
pens to the paper, because the japan forms a part of its 
substance. 

It may be observed, that only wood, paper, leather, 
and similar substances, require priming ; metals require 
none, because they admit no varnish into them, and 
therefore the ground is applied to them immediately. 

The priming and grounds are all laid on with brushes 
made of bristles : the painting will of course often re- 
quire a camels'-hair pencil. 

Of Japan Grounds, 

Red. — Vermilion makes a fine scarlet, but its appear- 
ance in japanned work is much improved by glazing it 
with a thin coat of lake, or even rose pink. 

Indian lake, when good, is perfectly soluble in spirits 



MISCELLANEOUS RECEIPTS. 335 

of wine, and produces a fine crimson, but is not often to 
be obtained. 

Yellow. — King's yellow, turbith mineral, and Dutch 
pink, all form very bright yellows, and the latter is very 
cheap. Seed-lac varnish assimilates with yellow very 
well ; and when they are required very bright, an im- 
provement may be effected by infusing turmeric in the 
varnish which covers the ground. 

Green, — Distilled verdigris laid on a ground of leaf 
gold, produces the brightest of all greens ; other greens 
may be formed by mixing king's yellow and bright prus- 
sian blue, or turbith mineral and prussian blue, or Dutch 
pink and verdigris. 

Blue. — Prussian blue, or verditer glazed with Prussian 
blue or smalt. 

White. — White grounds are obtained with greater dif- 
ficulty than any other. One of the best is prepared by 
grinding up flock-white, or zinc-white, with one sixth of 
its weight of starch, and drying it ; it is then tempered, 
like the other colours, using the mastic varnish for com- 
mon uses ; and that of the best copal for the finest. Par- 
ticular care should be taken, that the copal for this use 
be made of the clearest and whitest pieces. Seed-lac 
may be used as the uppermost coat, where a very deli- 
cate white is not required, taking care to use such as is 
least coloured. 

Black. — Ivory-black or lamp-black ; but if the lamp- 
black be used, it should be previously calcined in a closed 
crucible. 

Black grounds may be formed on metal, by drying 
linseed oil only, when mixed with a little lamp-black. 

The work is then exposed in a stove to a heat which 
will render the oil black. The heat should be low at 
first, and increased very gradually, or it will blister. This 
kind of japan requires no polishing. It is extensively 
used for defending articles of iron-mongery from rust. 

Tortoise-shell ground for metal. — Cover the plates 
intended to represent the transparent parts of the tor- 
toise-shell, with a thin coat of vermilion in seed-lac 



336 MISCELLANEOUS RECEIPTS. 

varnish. Then brush over the whole with a varnish 
composed of linseed oil boiled with umber until it is 
almost a black. The varnish may be thinned with oil 
of turpentine before it is used. When the work is done, 
it may be set in an oven, with the same precautions as 
the black varnish last named. a-jno 

Polishing of varnished and japanned work. 

Pictures and other subjects, to which only a single 
coat or two of thin varnish is given, are generally left to 
the polish which the varnish naturally possesses, or 
brightened only by rubbing it with a woollen cloth, after 
it is dry; but wherever several coats of varnish or 
japan are laid on, a glossy surface is produced by the 
means used to polish metals ; the surface having been 
suffered to become completely dry and hard. 

When the coat of varnish is very thick, the surface 
may be rubbed with pumice-stone and oil, until it be- 
comes uniformly smooth; the pumice should first be 
reduced to a smooth flat face by rubbing it on a piece of 
freestone, or something to answer the same purpose. 
The japanned or varnished surface may afterwards be 
rubbed with pumice reduced to an impalpable powder. 
The finishing may be given by oil and woollen rag only. 

When the varnish is thinner, and of a more delicate 
nature, it may be rubbed with tripoli or rotten-stone, in 
fine powder, finishing with oil as before. When the 
ground is: white, putty or Spanish w^hite, finely washed, 
may be used instead of rotten-stone, of which the colour 
might have some tendency to injure the ground. 

Pi^eparation of Drying Linseed Oil, 

Frequent reference has been made to the tise of drying 
linseed oil : it may be necessary to observe, that to render 
linseed oil drying consists simply in mixing it with litharge, 
or any oxide of lead, boiling it slowly for some time, and 
straining it from the sediments after it has stood to clarify. 
The oil thus treated, beomes thicker as it imbibes oxygen 
from the oxide, and acquires the property of drying much 



MISCELLANEOUS RECEIPTS. 337 

sooner than before. An ounce of litharge may be used 
in every pound of oil. 

To render Boots and Shoes water-proof, 

Takc one pint of drying oil, two ounces of yellow wax, 
two ounces spirits of turpentine, and half an ounce of 
Burgundy pitch, melt them over a slow fire, and thorough- 
ly incorporate them by stirring. Lay this mixture on 
new shoes and boots, either in the sun or at some dis- 
tance from the fire, with a sponge or brush, and repeat 
the operation as often as they become dry, until they are 
fully saturated. The shoes and boots thus prepared, 
ought not to be worn until the leather has become per- 
fectly dry and elastic. They will then be found imper- 
vious to moisture, and their durability will be increased. 

Method of preparing a cheap Substitute for Oil Paint. 

It often happens that people do not choose, or cannot 
employ oil-painting in the country, either because it does 
not dry soon enough, and has a disagreeable smell, or 
because it is too costly. Ludicke employed with the 
greatest success the following composition for painting 
ceilings, gates, doors, and even furniture. 

Take fresh curds, and bruise the lumps on a grinding- 
stone, or in an earthen pan or mortar, with a spatula. 
After this operation, put them in a pot with an equal 
quantity of lime, well quenched, and become thick 
enough to be kneaded : stir the mixture well, without 
adding water, and a whitish semi-fluid mass will be ob- 
tained, which may be applied with great facility Hke 
paint, and which dries very rapidly. It must be employed 
the day it is prepared, as it will become too thick the 
following day. Ochre, armenian bole, and all colours 
which hold with lime, may be mixed with it, according 
to the colour desired ; but care must be taken, that the 
addition of colour made to the first mixture of curds and 
lime, contain very little water, or it will diminish the 
durability of the painting. 

When two coats of this painting have been laid on, it 
29 



338 MISCELLANEOUS RECEIPTS. 

may be polished with a piece of woollen cloth, or other 
proper substance, and it will become as bright as varnish. 
This kind of painting, besides its cheapness, possesses the 
advantage of admitting the coats to be laid on and pol- 
ished in one day ; as it dries speedily, and has no smell. 

A Cement which answer's for cast iron Pipes, or 
wooden Logs, 

Take 12 or 14 lbs. of fine cast iron borings, put them 
in a vessel with as much water as will just wet them 
through; mix with them ^ lb. of pounded sal ammo- 
niac, and 2 oz. of flour of sulphur; mix all well together, 
and let stand three or four hours : they are then ready 
for use. If not used immediately, cover them with water 
till used. 

Bronzing. 

Bronze of a good quality acquires, by oxidation, a fine 
green tint, cdWeA patina antiqua. Corinthian brass re- 
ceives, in this way, a beautiful clear green colour. This 
appearance is imitated by an artificial process, called 
bronzing. A solution of sal ammoniac and salt of sorel 
in vinegar is used for bronzing metals. Any number of 
layers may be applied, and the shade becomes deeper in 
proportion to the number applied. For bronzing sculp- 
tures of wood, plaster-figures, &c., a composition of yel- 
low ochre, Prussian blue, and lamp-black, dissolved in 
glue-water, is employed. 

Caoutchouc, or India Rubber, how dissolved, uses, Sf*c. 

Caoutchouc is brought principally from South Ameri- 
ca : the juice, obtained from incisions, is applied in suc- 
cessive layers, over a mould of clay, and dried by exposure 
to the sun, and to the smoke from burning fuel. When 
perfectly dry, the mould is broken, leaving the caout- 
chouc in the form of a hollow ball. It is insoluble in 
alcohol and in water. Sulphuric ether, when purified by 
washing in water, dissolves it ; and, by evaporation, the 
caoutchouc may be discovered unchanged. 



MISCELLANEOUS RECEIPTS. 339 

Oil of turpentine softens it, and forms with it a sort of 
paste that may be spread as a varnish ; but it is very- 
long in drying. The fluid now commonly used to dissolve 
it is the purified naphtha from coal tar, which is, at the 
same time, a cheap and effectual solvent, and which 
does not change its properties. This solution is employed 
to give a thin covering of caoutchouc to cloth, which is 
thus rendered impervious to moisture. Caoutchouc is 
also readily soluble in cajeput oil. 

Caoutchouc, from its softness, elasticity, and impene- 
trability to water, is applied to the formation of cathe- 
ters, bougies, and tubes for conveying gases. These 
are formed by twisting a slip of it round a rod, and 
causing the edges to adhere by pressure, when softened 
by maceration in warm water. It is also used very ex- 
tensively in this country for over-shoes ; and its solution 
in oils forms a flexible varnish. 

The following Composition will render Boots or Shoes 
impervious to Water. 

Take neat's-foot oil, and dissolve in it caoutchouc, a 
sufficient quantity to form a kind of varnish ; rub this on 
the boots. This is sufiicient. 

N. B. The oil must be placed where it is warm, the 
caoutchouc put into it in parings. It will take several 
days to dissolve it. 

An excellent Salve for Cuts, Bruises, Sores, SfC. 

Take 1^ oz. of olive oil, 2 oz. of white diacula, and 2 
oz. of bees'-wax ; let these ingredients be dissolved toge- 
ther, and the salve is formed. This salve I have tried 
to my satisfaction, and found it answer exceedingly well. 

Various Cements, 

The joints of iron pipes, and the flanges of steam en- 
gines, are cemented with a mixture composed of sulphur, 
and muriate of ammonia, together wdth a large quantity 
of iron chippings. 

The putty of glaziers is a mixture of linseed oil and 



340 MISCELLANEOUS RECEIPTS. 

powdered chalk. Plaster of Paris, dried by heat, and 
mixed with water, or with rosin and wax, is used for 
uniting pieces of marble. A cement composed of brick- 
dust and rosin, or pitch, is employed by turners, and 
some other mechanics, to confine the material on which 
they are working. Common paint, made of white lead 
and oil, is used to cement china-ware. So also are resi- 
nous substances, such as mastic and shell-lac, or isinglass 
dissolved in proof-spirit or water. The paste of book- 
binders, and paper-hangers, is made by boiling flour. 
Rice-glue is made by boiling ground rice to the consist- 
ence of a thin jelly. Wafers are made of flour, isinglass, 
yeast, and white of eggs, dried in thin layers upon tin 
plates, and cut by a circular instrument. They are 
coloured by red lead cfec. Sealing-wax is composed of 
shell-lac and rosin, and is commonly coloured with ver- 
milion. Common glue is most usually employed for uniting 
wood and similar porous substances. It does not answer 
for surfaces impervious to water, such as metals, glass, 
&c. The cements mostly used in building are composed 
of lime and sand. The lime adheres to and unites the 
particles of sand. Cements thus made increase in strength 
for an indefinite period. Fresh sand wholly silicious and 
sharp, is the best. That taken from the sea shore is 
unfit for making mortar, as the salt is apt to deliquesce 
and weaken the mortar. The amount of sand is always 
greater than that of lime. From two to four parts of 
sand are used, according to the quality of the lime and 
the labour bestowed on it. 

An excellent Cement for Paper, Clothe SfC. or for the 
use of Block-Cutters 

Iiv fastening the hatting into the figures, is made by 
stirring a quantity of raw flour into a rather thin solution 
of gum-senegal water. 

Gilding. 

The art of gilding at the present day, is performed 
either upon metals, or upon wood, leather, parchment, 



MISCELLANEOUS RECEIPTS. 341 

or paper; and there are three distinct methods in 
general practice, viz. washy or water-gildings in which 
the gold is spread, whilst reduced to a fluid state, 
by solution in mercury ; leaf -gilding, either burnished 
or in oil, performed by cementing their leaves of gold 
upon the work, either by size or by oil ; japanners- 
gilding, in which gold dust or powder is used instead of 
leaves. Gilding on copper is performed with an amalgam 
of gold and mercury. The surface of the copper, being 
freed from oxide, js covered with the amalgam, and 
afterwards exposed to heat till the mercury is driven off, 
leaving a thin coat of gold. It is, also, performed by 
dipping a linen rag in a saturated solution of gold, and 
burning it to tinder. The black powder thus obtained 
is rubbed on the metal to be gilded, with a cork dipped 
in salt water, till the gilding appears. Iron or steel is 
gilded by applying gold leaf to the metal after the sur- 
face has been well cleaned, and heated until it has 
acquired the blue colour, which at a certain temperature 
it assumes. The surface is previously burnished, and the 
process is repeated when the gilding is required to be 
more durable. It is, also, performed by diluting a solu- 
tion of gold in nitro-muriatic acid, with alcohol, and 
applying to the clean surface. A saturated solution of 
gold in nitro-muriatic acid, and mixed with three times 
its weight of sulphuric ether, dissolves the muriate of 
gold, and the solution is separated from the acid beneath. 
To gild the steel, it is merely necessary to dip it, the sur- 
face being previously well polished and cleaned, in the 
ethereal solution, for an instant, and on withdrawing it, 
to wash it instantly by agitation in water. By this method 
steel instruments are very commonly gilt. 

Method of Preparing and Using Glue. 

Set a quart of water on the fire, then put in about 
half a pound of good glue, and boil them gently together 
till the glue be entirely dissolved, and of a due consistence. 

When glue is to be used, it must be made thoroughly 
hot, after which with a brush dipped in it besmear the 
29^ 



342 MlECELLANEOt'S RECEIPTS. 

faces of the joints as thick as possible ; then, clapping 
them together, glide or run thenn lengthwise one upon 
another two or three times, to settle them close, so let 
them stand till they are dry and firm. — Parchment-glue 
is made by boiling gently shreds of parchment in w^ater, 
in proportion of one pound of the former to six of the 
latter, till it be reduced to one quart ; the fluid is then 
strained from the dregs, and afterwards boiled to the 
consistence of glue. Isinglass-glue is made in the same 
way ; but this is improved by dissolving the isinglass in 
alcohol, by means of a gentle heat. 

China or Indian Ink. 

Dr. Lewis, on examining this substance, found that the 
ink consisted of a black sediment, totally insoluble in 
water, which appeared to be of the nature of the purest 
lamp-black, and of another substance soluble in water, 
and which putrefied by keeping, and when evaporated, 
left a tenacious jelly, exactly like glue, or isinglass. It 
appears probable, therefore, that it consists of nothing 
more than these two ingredients, and probably may be 
imitated with perfect accuracy by using a very fine jelly, 
like isinglass, or size, and the finest lamp-black, and in- 
corporating them thoroughly. The finest lamp-black 
known is made from ivory shavings, and thence called 
ivory black. 

Ivory Dyeing. 

This substance may be dyed or stained black, by a 
solution of brass and a decoction of logwood ; a green, by 
a solution of verdigris ; a red, by being boiled with Bra- 
zil-wood in lime-water. 

To prevent the smoking of lamp oil. 

Steep your wick in vinegar, and dry it well before 
you use it. 

Portable balls for removing spots from clothes in 

generah 
Take fuller's earth perfectly dried, so that it crumbles 
to powder, moisten it with the clear juice of lemons, 



IHISCELLANEOUS RECEIPTS. 343 

and add a small quantity of pure pearlash ; then work 
and knead the whole carefully together, till it acquires 
the consistency of a thick elastic paste : form it into con- 
venient small balls, and expose them to the heat of the 
sun, in which they ought to be carefully dried. In this 
state they are fit for use in the manner following: first 
moisten the spot on the clo_thes with water, then rub it 
with the ball just dissolved, and suffer it again to dry in 
the sun : after having washed the spot with pure water, 
it will disappear. 

Easy and safe method of discharging grease spots from 

woollen. 

FuLLER*s earth, or tobacco-pipe clay, being first wet on 
an oil spot, absorbs the oil as the water evaporates, and 
leaves the vegetable or animal fibres of cloth clean, on 
being beaten or brushed well. When the spot is occa- 
sioned by tallow or wax, it is necessary to treat the part 
cautiously by an iron on the fire, while the cloth is dry- 
ing. In some kind of goods, bran or raw starch may be 
used with advantage. 

To take spots out of Silk. 

Rub the spots with spirits of turpentine : this spirit 
exhaling, carries off with it the oil that causes the spot. 

To take spots out of Cloths^ Stuffs^ Silks, Cotton and 

Linen. 
Take one quart of spring-water, put in it a little fine 
w^hite powder about the size of a w^alnut, and a lemon 
cut in slices, mix these w^ell together, and let it stand 
twenty-four hours in the sun. This liquid takes out all 
spots, w^hether pitch, grease, or oil, as well in hats, as 
cloths and stuffi, silk or cotton, and linen. As soon as 
the spot is taken out, wash the place with clean water; 
for cloths of deep colour, add to a spoonful of the mix- 
ture, a quantity of water to dilute it. 

To render Clothe loind and rain proof 

Boil together 2 lbs. of turpentine, and 1 lb. of lith- 
arge in powder, and 2 or 3 pints of linseed oil. The 



344 MISCELLANEOUS RECEIPTS. 

article is then to be brushed over with this varnish, and 
dried in the sun. 

A Cement for broken Earthenware, 

Take 1 oz. oC dry cream cheese grated fine, and an 
equal quantity of quick-lime mixed well together, with 
3 oz. of skimmed milk, to form a good cement, when 
the rendering of the joint visible is of no consequence. 
If mixed without the milk, it perhaps might be stronger 
still. 

To take Mildew out of Linen. 

Take soap and rub it well ; then scrape some fine 
chalk, and rub that also in the linen ; lay it on the 
grass ; as it dries wet it a little, and it will come out at 
twice. 

Soda JVater, to make. 

Take 20 grains tartaric acid, 25 grains super-carbonate 
of soda : dissolve a lump of sugar, on which you have 
poured a drop of oil of lemon in two wine-glass-fulls of i 
water : add the tartaric acid : stir it till dissolved. Then 
dissolve the carbonate of soda in the like quantity of 
water, and pour the two solutions quickly together, and 
drink them off as rapidly as possible. 

To cure six Hams. 

Take 6 ozs. of salt-petre, 2 lbs. 10 ozs. of fine salt, 
41 lbs. of brown sugar or 1 gallon of molasses. Rub 
them with this mixture for one week every day ; then 
put them into a strong pickle (salt and water) for one 
month ; then smoke them, if to keep. Your pickle will, 
after the hams are taken out, be excellenj; for beef, 

Elastic Cement for Bells. 

Dissolve in good brandy, a sufficient quantity pf isin- 
glass, so as to be as thick as molasses. This composition 
I am credibly informed answers the purpose remarkably 
well. 



MISCELLANEOUS RECEIPTS. 345 

To soften Horn. 

Take 1 lb. of wood-ashes, add 2 lbs. of quick-lime, put 
them into a quart of water, let the whole boil until re- 
duced to one-third, — then dip a feather into it, if the 
plume comes off on drawing it out, then it is boiled 
enough ; when it is settled filter it off, and in the liquor 
then strained add shavings of horn, let them soak for 
three days, then rubbing oil on your hands work the horn 
into a mass, and print or mould it into whatever shape 
you want 

Varnish for Harness. 

Take ^ lb. of Indian rubber, 1 gallon of spirits of tur- 
pentine, dissolve enough to make it into a jelly by keeping 
almost new milk warm : then take equal quantities of 
good linseed oil (in a hot state) and the above mixture, 
incorporate them well on a slow fire, and it is fit for use. 

A Varnish for fastening the leather on top rollers in 
Factories. 

Dissolve 2f ozs. of gum-arabic in water, and add so 
much isinglass dissolved in brandy and it is fit for use. 

The manner of soldering Ferrules for Tool-handles, ^c. 

Take your ferrule, lap round the joining a small piece 
of brass-wire, then just w^et the ferrule, scatter on the 
joining-ground, borax, put it on the end of a wire, hold it 
in the fire till the brass fuses. It will fill up the joining, 
and form a perfect solder. It may afterwards be turned 
in the lathe. 

To make White-wash that will not rub off. 

Mix up half a pail full of lime and water, ready to put 
on the wall ; then take \ pint of flour, mix it up with 
water, then pour on it boiling water, a suflScient quantity 
to thicken it ; then pour it, while hot, into the white- 
wash ; stir all well together, and it is ready. 



346 MISCELLANEOUS RECEIPTS, 

An improved method of tempering Gravers, when 
too hard. 

Having heated a poker red-hot, hold the graver upon 
it, within an inch of the point, waving it to and fro, till 
the steel changes to a light straw colour ; then, having 
a piece of steel prepared for the purpose, with two nicks 
filed in it, one the shape of a lozenge, the other a square 
graver edge ; when heated to a straw colour, put the 
belly of the graver in one or other of the nicks, as the 
shape may be, and instead of plunging it into water, tal- 
low, or oil, hammer it on the back-side carefully, till 
cold, and you will have a far superior tool, if rightly 
managed, than by tempering the common way. This 
method closes up the pores of the steel when heated, 
and renders it more compact ; consequently, does not 
break. It would be well for dentists to manage tools on 
this principle, for good service and utility. 

Easy way of cleaning the Hands, for Dyers, Col- 
ourers, SfC. 

Take a small quantity of pot-ash or pearl-ash in your 
hand, pour into it a small quantity of water, rub it well 
all over your hands with a little sand, then wash it offj 
take in your hand a small quantity of chemic (chloride 
of lime,) pour a little water into it, and rub it well on 
the hands in a semi-liquid state;. wash the hands well in 
water, and they will be clean. If not perfectly clean, 
repeat the operation. 

Method of keeping the Hands soft and pliable in 
all situations. 

Rub the hands well in soap till a lather is produced ; 
then rub on a sufficient quantity of sand to let the soap 
and water predominate ; after well rubbing, wash well 
in warm water. Repeat this two or three times a day, 
as circumstances may require, and the hands will be kept 
perfectly soft 



MISCELLANEOUS RECEIPTS. 347 

Ink-Powder, 

Infuse a \ lb. of galls powdered, and 1|^ ozs. of pome- 
granate peels, in a ^ gallon of soft water for a week, in 
a gentle heat, and then strain off the fluid through a 
cloth. After which, add to it 4 oz. of vitriol dissolved in 
a pint of water, and let them remain for a day or two, 
preparing in the mean time a decoction of logwood, by- 
boiling a half pound of the chips in a half gallon of 
water, till one third be evaporated, and then straining 
the remaining fluid while it is hot. Mix the decoction 
and the solution of galls and vitriol together, and add 
2i ozs. of gum-arabic or the whitest of gum-senegal, 
and then evaporate the mixture over a common fire to 
1 quart, when the remainder must be put into a proper 
vessel, and reduced to dryness, by placing it in a suf- 
ficiently warm place, or letting it hang in boiling water. 
After the whole of the liquid is evaporated, the residue 
must be well powdered. When wanted for use, all that 
is needed, is to dissolve the powder in water. 

To give iron a temper to cut porphyry. 

Make your iron red-hot, and plunge it into distilled 
water from nettles, acanthus, and pilosella ; or in the 
very juice pounded out from these plants. 

To prevent iron from rusting. 

Warm your iron till you cannot bear your hand on it 
without burning yourself. Then rub it with new and 
clean white wax. Put it again to the fire till it has 
soaked in the wax. When done, rub it over with a piece 
of serge. This prevents the iron from rusting after- 
wards. 

To dye in Gold, Silver Medals, or laminas, through and 
through. 

Take Glauber salt, dissolve it in warm water, so as to 
form a saturated solution. In this solution put a small 
proportionate quantity of calx, or magister of gold. Then 



348 MISCELLANEOUS RECEIPTS. 

put and digest in it, silver laminas cut small and thin, 
and let them lay 24 hours over a gentle fire. At the end 
of this term, you will find them thoroughly dyed gold 
colour, inside and out. 

An oily one ounce of which will last longer than one 
pound of any other. 

Take fresh butter, quick-lime, crude tartar, and com- 
mon salt, of each equal parts, which you pound and mix 
well together. Saturate it with good brandy, and distil 
it in a retort over a gradual fire, after having adapted 
the receiver, and luted well the joints. 

To make Corks for bottles. 

Take wax, hog's lard, and turpentine equal quantities 
or thereabouts. Melt altogether and stop your bottles 
with it. 

An oil to prevent pictures from blackening. It may 
serve, also, to make cloth to carry in the pocket against 
wet weather. 

Put nut or linseed oil into a phial, and set it in the 
sun to purify it. When it has deposited its dregs at the 
bottom, decant it gently into another clean phial, and set 
it again in the sun as before. Continue so doing till it 
drops no more faeces at all. And with that oil, you make 
the above described compositions. 

To gild on Calf and Sheep Skin. 

Wet the leather with the white of eggs; when dry, 
rub it with your hand and a little olive oil, then put the 
gold leaf and apply the hot iron to it. Whatever the 
hot iron shjali not have touched will go off by brushing. 

To dye Wood Red. 

Take chopped brazil wood, and boil it well in water, 
strain it through a cloth. Then give your wood two or 
three coats, till it is the shade wanted. If wanted a 
deep red, boil the wood in water impregnated with alum 



MISCELLANEOUS RECEIPTS. 349 

and quick-lime. When the last coat is dry, burnish it 
with the burnisher, and then varnish. 

Another method to dye Wood Red, 

Take vermilion and Spanish brown ; make them thin 
with linseed oil and turpentine. Rub it on with a cloth 
in such a manner as to show the grain of the wood ; w^hen 
dry, varnish. The proportion of vermilion and Spanish 
brown, must be in proportion to the fineness of the shade 
wanted. 

To imitate Ebony. 

Infuse gall-nuts in vinegar, wherein you have soaked 
rusty nails; then rub your wood with this; let it dry, 
polish and burnish. 

To produce various undulations on Wood. 

Slack some lime in chamber ley. Then with a brush 
dipped in it, form your undulations on the wood accord- 
ing to your fancy. And, when dry, rub it well with a 
rind of pork. 

To soften Ivory. 

In three ounces of spirits of nitre, and fifteen of spring- 
water, mixed together, put your ivory a soaking. And 
in 3 or 4 days, it will be soft so as to obey your fingers. 

To dye Ivory thus softened, 

1. Dissolve, in spirits of wine, such colours as you want 
to dye your ivory with. And when the spirit of wine 
shall be sufficiently tinged with the colour you have put 
in, plunge your ivory in it, and leave it tjfiere till it is 
sufficiently penetrated with it, and dyed inwardly. Then 
give that ivory what form you please. 

2. To harden it afterwards, wrap it up in a sheet of 
white paper, and cover it with decrepitated common salt, 
and the driest you can make it to be ; in which situation 
you shall leave it only 24 hours. 

30 



350 MISCELLANEOUS RECEIPTS. 

To whiten ivory, even that lohich has turned a brown 
yellow. 

1. Slack some lime in water, put your ivory in that 
water, after decanted from the ground, and boil it till it 
looks quite white. 

2. To polish it afterwards, set it in the turner's wheel, 
and after having worked it, take rushes and pumice- 
stones, subtile powder with water, and rub it all till it 
looks perfectly smooth. Next to that, heat it by turning 
it against a piece of linen, or sheep-skin leather, and 
when hot, rub it over with a little whitening diluted in 
oil of olive ; then with a little dry whitening alone, and 
finally with a piece of soft white rag. When all this is 
performed as directed, the ivory will look remarkably 
white. 

To ivhiten Bones. 

Put a handful of bran and quick-lime together, in a 
new pipkin, with a sufficient quantity of water, and boil 
it. In this put the bones, and boil them also till perfect- 
ly freed from greasy particles. 

To petrify Wood, SfC. 

Take equal quantities of gem-salt, rock-alum, white 
vinegar, chalk, and pebbles powder. Mix all these in- 
gredients together : there will happen an ebullition. If, 
after it is over, you throw in this liquor any porous mat- 
ter, and leave it there a soaking four or five days, they 
will positively turn into petrifactions. 

A preparation for Tortoise-shelL 

Take orpine, quick-lime, pearl-ashes, and aquafortis. 
Mix well altogether, and put your horn or tortoise-shell 
in it to soak. 

To dye Bones any colour. 

Boil the bones first for a good while ; then in a ley of 
quick-lime mixed with chamber ley, put either verdigris, 
or red or blue chalk, or any other ingredient fit to pro- 



MISCELLANEOUS RECEIPTS. 351 

cure the colour you want to give to the bones. Lay the 
bones in the Hquor, and boil them, they will be perfectly 
dyed. 

To write on Silver with a black which will never go off. 

Take burnt lead, and pulverize it. Incorporate it next 
with sulphur and vinegar, to the consistency of a paint- 
ing colour, and write with it on any silver plate. Let it 
dry, then present it to the fire so as to heat the work a 
little, and it is finished. 

To restore Wine that is turned sour or sharp. 

Fill a bag with leek-seed, or of leaves or twisters of 
vine, and put either of them to infuse in the cask. 

To correct a bad taste and sourness in Wine. 

Put in a bag the root of wild horse-radish cut in bits. 
Let it down in the wine, and leave it there two days : 
take this out, and put another, repeating the same till 
the wine is perfectly restored. Or fill a bag with wheat : 
it will have the same effect. 

To cure those who are too much addicted to drinking 

Wine. 

Put in a sufficient quantity of wine, three or four 
large eels, which leave there till quite dead. Give that 
wine to the person you want to reform, and he or she 
will be so much disgusted with wine, that though they 
formerly made use of it, they will now have an aversion 
to it. 

To increase the sharpness and strength of Vinegar. 

Boil two quarts of good vinegar, till reduced to one ; 
then put it in a vessel and set it in the sun for a week. 
Now mix the vinegar with six times its quantity of bad 
vinegar in a small cask : it will not only mend it, but 
make it strong and agreeable. 

To make Vinegar ivith loater. 

Put 30 or 40 lbs. of wild pears in a large tub, where 
you leave them three days to ferment. Then pour some 



352 MISCELLANEOUS RECEIPTS. 

water over them, and repeat this every day for a month : 
at the end of which it will make very good vinegar; 
the goodness of which may be increased by the above 
method. 

A dry portable Vinegar > 

WAsh well half a pound of white tartar with warm 
water, then dry it, and pulverize as fine as possible. 
Soak that powder with good sharp vinegar, and dry it 
before the fire or in the sun. Re-soak it as before with 
vinegar, and dry it as above, repeating this operation a 
dozen of times. By these means you will have a very 
good and sharp powder, which turns water instantly into 
vinegar. It is very convenient to carry in the pocket, 
especially when travelling. 

Horn to extract the essential oil from any floioer. 

Take any flowers you like, which stratify \\\i\i com- 
mon sea-salt in a clean earthen glazed pot. When thus 
filled to the top, cover it well, and carry it to the cellar. 
Forty days afterwards put a crape over a pan, and empty 
the whole to strain the essence from the flowers by pres- 
sure. Bottle that essence and expose it 4 or 5 weeks in 
the sun, and dew of the evening to purify. One single 
drop of that essence is enough to scent a whole quart of 
water. 

To make Mutton Suet Candles, in imitation of Wax, 

1. Throw quick-lime in melted mutton suet; the lime 
will fall to the bottom, and carry along with it all the 
dirt of the suet, so as to leave it as pure and as fine as 
wax itself. 

2. Now if to one part of the suet, you mix three of 
real wax, you will have a very tine, and to appearance 
a real wax candle, at least the mixture could never be 
discovered, nor even in the moulding way for ornaments. 



RECEIPTS ON DYEING. 353 



: RECEIPTS ON DYEING. 

General remarks on Dyeing. 

Cleanliivess in dyeing is very essential. The vessel, 
and the articles to be dyed, must be ridded of grease and 
djrt; as grease resists the colouring particles, and dirt 
leaves a stain. 

Soft water should always be used for dyeing. Vessels 
used for dyeing snaall articles, should generally be wash 
hand basons, small copper and tinned pans, and suf- 
ficiently large that the dyeing liquor be not spilt by dip- 
ping the article in and out when dyeing. 

The quantity of liquor generally necessary for dyeing 
a dress of muslin, crape, sarsnet, cambric, &c. is about 
three quarts ; for a larger dress a proportionable quantity. 

The dyeing utensils are simple^ being composed of 
tubs, kettles, horse, or a couple of lathed benches, for 
the purpose of placing the goods upon, when they come 
from the dye. The horse may be in form of a carpen- 
ters' stool. A doll which is used for beating blankets, 
counterpanes, &c. in the tub in order to clean them. For 
this doll some use an article similar to a pavior's mall, but 
of smaller dimensions : others have a circular piece of 
wood 2 inches thick, in which 4 legs are fastened, on the 
under side, and in the centre a pretty long handle, wath 
a cross piece put through it to v/ork it with. Against 
the wall or a post, fasten a hook or pin to put on your 
skeins, and with a small stick wring them out. In fancy 
dyeing the various shades of cambric, a winch is in fre- 
quent use. 

The liquors should always be stirred with a spoon, rod, 
or any thing that is clean, previous to the article being 
dipped in it, to cause the colouring particles to be equally 
diffused, so that the article to be dyed receives its colour 
uniformly, and it is also necessary that the article be 
Hioved in and out quick, and opened to receive the 
colour more evenly. 
30^ 



354 RECEIPTS ON DYEING. 

Colours generally look much darker when wet, there- 
fore, allowance should generally be made for drying, 
which should always be done in a warm room, pinned or 
stretched to a line. 

(1.) Aluming 

Is a preparation necessary for some colours in order to 
receive the colouring particles, such as crimson, scarlet, 
purple, and some other colours. If any article is direct- 
ed to be alumed, be careful to rid it well of the soap- 
suds, as alum turns soap to grease. When the article is 
put in the alum liquor, it is to be well dipped in and out, 
and opened, to receive this preparation more equally, 
for an hour, or all night if circumstances admit, and when 
alumed, it must be w^ell wrung out, and rinsed in two 
waters, and then dyed, the sooner the better, before get- 
ting dry. Note. — The aluming of silks ought to be done 
cold, or it will be deprived of its lustre. 

(2.) Preparing of the dye'liquors, or scalding the woods. 

Having something like the end of a tub, about one 
foot deep, with a copper bottom, bored full of holes 
about a quarter of an inch in diameter ; lay a piece of 
rather coarse sheeting on this, lay it altogether on another 
tub ; fill it with the wood to be scalded ; then having 
a copper-boiler full of boiling water, fill the tub which 
contains the wood with boiling water, stir it during the 
time it is going through; fill it up again, and so repeat 
the operation till you have got all the strength from the 
wood. The criterion by which to know when the 
strength is gone from, the wood, is the paleness of the 
liquor as it runs through. This operation is considered 
superior to boiling the wood in a copper-boiler, especially 
for the ground- woods ; but either way will answer. The 
method of rendering the liquor stronger, of course, is by 
evaporation, in a copper-vessel, with a constant fire un- 
der it. The chips of dye-woods are generally superior 
to the ground-woods, as they are not so likely to be adul- 
terated. 



RECEIPTS ON DYEING. 355 

(3.) Pink on Silh 

After aluming, (see receipt No. 1.) handle the goods 
to be dyed in peach-wood liquor, till the colour desired ; 
then take out and put in a little alum liquor, handle the 
goods a little longer, take out, rinse in water, and finish. 
Noxe. — In most cases, where the shade is not dark 
enough, the operation must be repeated. 

(4.) Brown on Silk, 

Alum your silk : (see No. L) Then take one part of 
fustic liquor, and three parts of peachwood Hquor; han- 
dle in these till it becomes a good brown ; (a little log- 
wood liquor will darken your shade, if required,) hedge 
out, and put in a little alum-water; again put in your 
goods, handle a little longer, then take out, drain, rinse 
well, and finish. Note. — By varying the peachwood and 
fustic, various shades may be obtained. 

(5.) GreeJi on Silk, 

Take green ebony, boil it in water, let it settle ; take 
the clean liquor as hot as you can bear your hands in it, 
handle in it your goods till of a bright yellow; then take 
water, and put in a little sulphate of indigo ; handle your 
goods in this till of the shade wanted. Note. — The 
ebony may previously be boiled in a bag, to prevent it 
from sticking to the silk. 

(6.) Sulphate of Indigo, 

Take 3 lbs of vitriol, 1 lb. of ground indigo; put in a 
little at a time, and keep stirring till all dissolved. Let 
stand 24 hours, and ready. 

(7.) Blue on Silk, 

Indigo, same as No. 5, green; you will have a blue. 
Note. — The silk ought to be boiled in w^hite soap and 
water, and made quite w^hite, and then rinsed in luke- 
warm water. 



356 RECEIPTS ON DYEING* 

e 

(8.) Black on Silk. 

Take 1 oz. of bluestone of vitriol, 2 oz. of copperas, ^ 
oz. of nitrate of iron; mix all together with as much 
water as will do one piece ; have the w^ater a little 
warm ; hedge in this six times, backward and forward, 
take out, rinse in water; take another tub, put in it as 
much logwood hquor, that has in it 1 lb. of logwood, 1 
oz. of fustic liquor ; hedge in this liquor with a sufficient 
quantity of water, till black ; wash out, and finished. 
Note. — In both processes, let them have a chance to air 
in drying. 

(9.) Blue Black on Silk. 

First run through a mordant of nitrate of iron and 
water, then run through pearl-ash water, then through 
nitrate of iron again ; then put them through logwood 
liquor, with a little bluestone of vitriol dissolved in it. If 
not dark enough, repeat the operation. 

(10.) Maroon on Silk. 

To 3 lbs. of silk, take ^ lb. of Cudbear, put it in wa- 
ter, let it boil, then put in your silk, let it boil a few 
minutes, keep your silk well handled, take out, and you 
will have a good handsome colour. To change the 
shade, put in 2 lbs. of common salt ; operate as before : 
this will vary the shade. To vary it still further, take 
the silk, after boiling it the first time without the salt, 
handle it in pearl-ash water, or in cream of tartar, and 
you will have a handsome blue. 

(11.) Orange on Silk or Cotton. 

Take 1 lb. of silk, 1 oz. of arnotta, 2 oz. of pearl-ash, 
boil them well together, turn in your goods ; when boiled 
10 minutes, take out, wash, and finished. 

If this orange is dark, handle the goods at hand-heat. 

Note. — These goods must be well washed out in soap, 
and in aluming them, you may use a little sugar of lead. 



RECEIPTS ON DYEING. 357 

(12.) Grey on Silk, 

For a silk dress. Take 4 or 6 oz. of fine powdered 
galls, pour on them boiling water, handle your silk in 
this for 20 or 30 nninutes; in another form, dissolve a 
piece of green copperas, about the size of a nut ; handle 
your silk through this, and it will be a grey, more or less 
dark according to the quantity of drugs. 

(13.) Slate on Silk. 

To make a slate, take another pan of warm water 
and about a tea-cup full of logwood liquor, pretty strong, 
and a piece of pearl-ash, of the size of a nut ; take the 
above grey-coloured goods, and handle a little in this 
liquor, and it is finished. Note. — If too much logwood 
is used, the colour will be too dark. 

(14.) Olive on SilL 

By adding a little fustic liquor to the above slate, it will 
form an olive : it may be necessary to run them through 
a v/eak pearl-ash water to sadden them. Wash in two 
waters for the above three colours. They will keep 
their colour very well. 

(15.) Stone colour on Silk. 

Take the coloured grey (see receipt No. 12.) Add a 
sufficient quantity of purple archil to the grey liquor. 
To give them a red sandy cast, add a little red archil: 
simmer the silk in this a few minutes. Rinse in one or 
two cold waters. Dry in the air. The red archil is 
made from purple archil, by adding a small quantity of 
vitriol and water, which will redden it. 

(16.) To dye a Silk Dress Brown, 

Take 8 oz. of sumach ; 4 oz. of logwood ; 8 oz. of 
camwood or madder; boil these drugs in water, then 
cool down your liquor; wet out your silks; then enter 
them ; handle well ; wash out as usual. For a mulber- 
ry cast, add as much purple archil as may be necessary. 



358 RECEIPTS ON DYEING. 

(17.) Drab on Silk. 

For a silk dress. Take 4 oz. of archil, one oz. of 
madder ; enter and handle the goods ; this may be sad- 
dened, by taking out your goods and dissolving in the 
liquor a piece of green copperas, the size of a nut ; 
again handle in this liquor ; or, what is still better, in- 
stead of copperas, use a little pearl-ash to sadden with. 

(18.) Dove on Silk, 

Take Brazil logwood and sumach ; vary the quantities 
as you want your shade ; boil them in water, then enter 
your goods, handle well, and sadden with green copperas. 

(19.) Yellow on Silk, 

Boil quercitron barks in a copper pan for 20 minutes, 
any quantity you please. Dip out a suj3icient quantity 
to cover your silk, in another copper pan, or tinned ves- 
sel, into which add a small quantity of muriate of tin ; 
pass your silks first through warm water, and wring them 
out; then put them into this pan of dye-water, and han- 
dle them with a clean stick, till cold ; when cold, take 
out, throw out your liquor, take from the first pan as 
much liquor as before, handle in this 10 minutes, then 
add muriate of tin according to shade wanted. Rinse 
out in its own liquor and dry in a warm room. Annetto 
aflfords an orange yellow with equal quantities of pearl- 
ash, and gives out its colour to silk in warm water. 
Turmeric gives out its colour in a similar manner. The 
roots of Barbary afford a yellow of themselves, when 
boiled in water. 

(20.) Crimson on Silk. 

Take Cudbear, boil it in water; then just rinse or 
handle your silks in it for a few minutes, you have the 
shade wanted. Chamber ley or any alkaline solution 
will change the colour. 

(21.) Flesh Colour on Silk, 
Having first thoroughly cleaned your silk in the usual 
manner, rinse in warm, w^ater ; then handle them in a 



RECEIPTS ON DYEING. 359 

very slight water of alum and tartar, so slight that you 
could hardly taste it. Then if you have been dyeing 
Pinks, No. 3, receipt, take some of the old liquor, handle 
in it till of the shade wanted. The liquor must not be 
too strong, or the shade will be too heavy. 

(22.) Brown on. Woollen Cloth, or Clothes of any 
description. 

The quantity of woods to be regulated according to 
the quantit)^ of goods to be dyed. For instance, a pair 
of men's pantaloons, being first well cleaned from all 
grease : take 1 lb. of red-wood, hypernick, or peach- 
wood ; 1 lb. of fustic, put them in a copper kettle, boil 
them, then cool down so as to bear in it your hand ; then 
put in a small quantity of cream of tartar, agitate the 
water; then enter your goods, handle them till they come 
to a boil, let it boil 5 or 10 minutes; take out the goods, 
put in a strong solution made of 4 oz. of copperas, again 
cool down, re-enter the goods, again bring them to a 
boil ; take out, rinse well in water, finished. 

This process makes a good substantial brown, and 
might be varied in the shade by varying the quantities 
of woods in their proportion, also, by adding a little 
alum in the saddening. This is somewhat of an olive 
cast. 

(23.) A Brown on the Red cast. 

lotTAKE 2 of red-wood, 1 of fustic, proceed in every re- 
spect as in No. 22, receipt, the desired shade will be 
required. The quantity of dye-woods may be regulated 
according to the quantity of goods to be dyed, in No. 22, 
also, the copperas and tartar. On woollen of course. 

(24.) Olive Brown. 

For a pair of pantaloons, providing they weigh 3 lbs.; 
take 1 lb. of fustic, 1 oz. of logwood, 4 oz. of common 
Madder, 2 oz. of peachwood ; boil them up, then cool 
down your liquor, enter your pantaloons, bring the liquor 
to a boil, let it boil half an hour, occasionally turning 



360 RECEIPTS ON DYEING. 

over ; take out, cool down your liquor, put in 2 oz. of ^ 
dissolved copperas, handle until deep enough. For wool : 
Any quantity of yarn may be dyed on the same prin- 
ciple. 

(25.) A Brown inclining to Snuff, 

Take any quantity of woollen goods, use for every 
lb. 1^ or 2 lbs. of logwood ; first put your logwood into 
the copper vessel, bring it to a boil ; cool down, then 
enter your goods, bring them to boil, half an hour or 
longer, if a large quantity ; take out, wash and finished. 
Put, however, a little sumach, about 2 oz. to the lb. of 
logwood. This will be a good shade of brown. To alter 
this shade, put into your liquor a proportionally small 
quantity of alum liquor, again enter the goods, you will 
have a good handsome shade on silk, as well as woollen. 

(26.) A Black inclining to Purple on Wool and Silk. 

Take 4 lbs. of logwood, 1 lb. of sumach, boil them in 
a suflicient quantity of water; cool down with water 
enough to dye 4 or 5 lbs. of silk or wool ; enter the goods, 
bring them to boil, for ten minutes ; take out, partly cool 
down, put in about 1 lb. of copperas ; again enter your 
goods, bring them to a boil, take out, wash and finish. 
Chiefly intended for wool. 

N. B. A pair of pantaloons or any other article which 
is old, would not need to be so particular in quantity of 
dye-stuffs, nor length of time. It will also answer for 
cotton, and that without sumach, if the sumach is not 
at hand. This is intended chiefly for woollen. 

(27.) A Black inclining to Broion on Silk and Woollen. 

Take one part of sumach, one of logwood, one of hy- 
pernick or peachwood ; boil the dye-stuffs, cool down ; 
put in the silk or woollen according to the quantity of 
your dye-woods, bring them to a boil, for ten minutes, 
take out the goods, cool down ; having put in a sufficient 
quantity of dissolved copperas, again enter the goods, 
bring to a boil, take out, wash well and finish. 



RECEIPTS ON DYEING. 361 

To mix the copperas with alum would materially alter 
the shade, if a variety was wanted. This is chiefly in- 
tended for wool. 

(28.) A Jet Black on Woollen or Woollen Cloth. 

For 7 lbs. of wool or woollen cloth, take 3J lbs. of log- 
wood, Jib. of sumach, |^ lb. of fustic; boil these drugs 
in a sufl^cient quantity of water for 20 minutes, cool 
down, put in your goods, bring to a boil half an hour, 
then take out, cool down your liquor; add copperas dis- 
solved in water \^ lbs., blue stone of vitriol 2 oz. ; again 
enter your goods, bring to a boil 15 minutes, take out, 
wash well in cold water, and finish. 

(29.) Blue Prussian on Woollen. 

Take any quantity of calcined copperas, dissolve it in 
warm water, strong, put in your goods, keep them well 
handled till the water comes nearly to a boil, still handle 
15 minutes; then rinse the goods in cold water; get up 
another kettle of 1 of wine to 3 of water, bring the 
water to hand heat ; put in your goods, handle half an 
hour ; again rinse in cold water ; get up another kettle 
of water, hand heat, and for each lb. of goods f lb. of 
prussiate of potash, put some oil of vitriol in the kettle, 
handle the goods half an hour, if the colour looks green, 
add a little more vitriol, handle half an hour longer, take 
out, wash in cold water, and finish. 

(30.) Green on Wool. 

For 6 lbs. of yarn, worsted, or cloth, take 3 lbs. of fus- 
tic, f of alum; boil them in a kettle 10 minutes, partly 
cool down; then put in a small tea-cup full of sulphate 
of indigo, rake it well up, enter yonr goods, bring up to 
a boil, keeping the goods well handled, let boil 20 min- 
utes, (if a larger quantity, boil longer in proportion,) take 
out, and if not blue enough, add a little more sulphate 
of indigo ; handle until deep enough. Rinse in cold wa- 
ter, and finish. 
31 



362 RECEIPTS ON DYEING. 

This shade may be altered in a variety of ways, by 
adding a little camwood, or logwood, in the first boiling. 

(31.) Lilac on Wool. 

Boil up any quantity of archil, according to the quan- 
tity of goods you want to dye ; cool the liquor a little, 
enter the goods, handle carefully, until the shade is deep 
enough, without boiling the liquor, take out, wash, and 
finish. 1 lb. of archil will dye 4c\ lbs of goods. Silk may 
be dyed in the same way. The shades may be altered 
by soda, pearl-ash, wine, or common salt, adding a little, 
and re-entering the goods before washing, and handling 
a little while longer. 

(32.) Drab on Woollen. 

For about 15 lbs of woollen goods, take f lbs of weld, 
9 oz. of madder, 4 oz. of logwood, 3 oz. of archil; put them 
in water, bring them to a boil for 10 or 15 minutes, cool 
down, enter the goods, boil 15 minutes, wind up; put in 
1 oz. of alum, Ij oz. of copperas, ground; boil a few 
minutes longer, during which time, handle well ; take 
out, wash, and finish. The above receipt may serve as 
a standard of procedure for all the drab shades, which 
may be altered at pleasure, that can be produced ; only 
varying the quantities of drugs, in some cases adding ar- 
chil, and in others, a little sulphate of indigo. Red tartar 
and camwood may also be used. The copperas and 
alum may be varied in quantity, or increased, or the 
alum left out ; thus varying the whole round. 

(33.) Red on Woollen. 

For 10 lbs. of woollen goods. Take 2 lbs. of alum, 
i lb. of red tartar ; boil the goods in this 1 hour ; (if a 
larger quantity of gOiDds boil longer time) then boil up 
4 J lbs. of peachwood in clean water, cool down to a 
scald, put in 2 oz. of No. 1, tin liquor, enter the goods, 
handle until dark enough, and finish. The goods must 
not be washed between the 1st and 2d operation. 



RECEIPTS ON DYEING. 363 

(34.) Slate on Woollen, 

For 10 lbs. of woollen goods. Take 10 lbs. of sumach, 
boil it up 10 minutes, cool down, put in your goods, bring 
them to a boil a few minutes, take out, put in 4 lbs. of 
copperas, dissolve, cool down ; re-enter the goods, bring 
them to a boil, take out, wash and finish. A quantity 
of iron liquor, such as the calico-printers use, would be 
preferable to copperas. This slate may be varied by 
varying the proportion of copperas and sumach ; also, by 
adding a little peachwood, or any other red- wood ; in this 
case, less copperas might be used. 

(35.) Yellow on Wool 

For 10 lbs. of wool. Bring a kettle of water to a 
scald or 180 degrees of heat, put in 4 lbs. of quercitron 
bark, (do not allow it to boil, as that would fetch out the 
tanning and dull the yellow) 1 lb, of alum, 6 oz. of 
cream of tartar, nearly a half pint of No. 1, tin liquor; 
stir up the liquor well, allow it to settle 15 minutes; 
enter the goods, keep in until dark enough. 

(36.) Orange on Wool. 

First dye the pattern to a full yellow. Then take a 
clean kettle of water, when a little warm, put in for the 
above goods 2 lb. of madder, peachwood, mongeat, or 
hypernick ; mongeat does very well : put in your goods, 
keep them well handled, bring the goods to a boil, let 
boil till dark enough, wash and finished. 

VARIOUS SHADES OF FANCY DYEING ON 
COTTON. 

(37.) For any quantity of Thread in Black. 

First take the thread, boil it in sumach and water ; 
then let it be immersed in lime-water, cold ; then in 
weak copperas water, cold; then in lime-water again, 
cold ; then in logwood liquor, w^arm ; take out, put some 
copperas liquor into your logwood liquor, again put in 
your goods, handle and finish. This makes a first-rate 
black. 



364 RECEIPTS ON DYEING. 

(38.) Turmeric yellow. 

Take about 3 lbs. of turmeric, put it in a small tub 
for the purpose, pour on it a tumbler of oil of vitriol, stir 
it well up, then pour on it hot water, about two gallons, 
stir this well up ; then having half a tub-full of water, 
boiling hot from the boiler, pour on it the contents of the 
small tub ; enter three pieces, 30 yards each, give them 
6 or 8 ends, as the workmen term it, fold up ; the next 
process, have another tub of water, put in it half a pale 
full of alum liquor, give the pieces 3 or 4 ends in this, 
take out and finish. Renew with the same quantity for 
the next 3 pieces, and so proceed. Note. — By the ends 
is meant rinsing the pieces backward and forward over 
the wince in the tub. A half a hogshead will answer 
the purpose. 

It will be understood that these cotton colours are in- 
tended for linings or cambrics. It will also be understood 
that the liquors must be prepared as in receipt. No. 2, 
or by boiling in a copper-cistern; the former is most 
generally adopted for this kind of dyeing. It will be 
necessary to have a number of tubs for the different li- 
quors ; and in dyeing various shades, to have the liquors 
prepared in readiness. 

(39.) Green on Cotton, 

Take as much hot fustic liquor as will cover 3 pieces, 
in which is put a very little lime liquor, put it in a tub, 
enter your goods, give them 5 ends, hedge them out; 
take another tub, half full of water (cold), put into it a 
sufficient quantity of blue-stone of vitriol liquor, to set 
the tub, about two quarts, enter your goods in this, give 
them five ends, hedge out, then take a couple of pail- 
fulls of the fustic liquor, renew the first tub, enter 3 
pieces more, and so proceed as at first ; then renew your 
blue vitriol tub with half the quantity of liquor, not 
taking any out, and proceed as at first. In this way do 
as many the first and second time, as you can finish that 
day ; then commence to finish them. Take half a tub- 



RECEIPTS ON DYEING, 365 

full of old fustic liquor that has been used once, and put 
to it 1^ pail-fulls of logwood liquor ; enter your pieces 
3 at a time, give them five ends, and finish. Renev^^ with 
a little more logwood liquor, enough to make them dark 
enough, having first thrown away a couple of pail-fulls 
from the tub, and renew with the same from the old tub, 
and so proceeed in finishing. 

(40.) Buff on Cotton. ^ 

Take as much hot fustic liquor and water, as will half 
fill a tub, enter 3 pieces, give them 5 ends, hedge out ; 
take another tub of lime-water cold, enter the same 
pieces, and give them 5 ends in this, take out, and in a 
short time they will be buff Renew your first and 
second tub, and proceed as at first. This is all required 
for buff 

(41.) Annetto Orange on Cotton. 

Having prepared your annetto liquor by boiling it in 
a copper vessel for 20 minutes ; take out your liquor, put 
it in a tub ; partly fill your boiler with Water, bring it to 
a boil, having kept in the boiler the sediment of the 
annetto, make it strong enough with annetto liquor, to 
the shade you want to dye ; enter 3 pieces when boiling, 
give them 3 ends, take out ; enter them into cold alum 
water, give them 4 ends, take out and finish. Renew 
your annetto boiler with a sufiicient quantity of annetto 
liquor, and proceed as before ; then renew your alum 
tub, proceed as before in the 2d process. This finishes 
them. 

The liquor that is left in the boiler at night, will do to 
boil the annetto in the next day, so that nothing is lost. 

(42.) Red an Cotton. 

Take 3 pieces, enter them into a tub with hot red- 
wood, or peach-wood liquor, give them 5 ends, then run 
them into your wince ; have another tub called the spirit 
tub close by, half full of cold watery put into it about 3 
tumblers full of spirits; then run the pieces from the 
31* 



366 RECEIPTS ON BYEING. 

other wince over the wince of the spirit tub, give them 
5 ends in the spirit tub, then wind them on the wince of 
the spirit tub, then back again to the red tub ; give them 
5 ends without having renewed the tub, they are finished. 
Throw away the red tub liquor, put in fresh liquor, 
and proceed as before ; but the spirit tub must be re- 
newed always; even at night it maybe left in a tub, and 
renewed the next day. 

(43.) Brown on Cotton. 

The first process is to give them 5 ends in hot sumach 
liquor, or let them lay all night in the large tub, same as 
for blacks; then give them 5 ends in copperas, hedge 
out, give them 5 ends in lime tub ; then hedge out, lay 
them one side till you get enough to finish that day. You 
next renew your tubs and repeat the operation as before. 
Then comes the. ^Bisting part. Make up a tub of hot 
red- wood liquor ; enter a piases, give them 5 ends, put 
the pieces one side the tub, put in some alum liquor, stir 
up, give them 5 ends more, hedge out and finished, 

04^^. Drab on Cotton, 

Take half a tub of hot sumach, and fustic liquor; 
more fustic than sumach, according to shade wanted ; 
enter 3 pieces, give them 5 ends, hedge out ; give them 
5 ends in the copperas tub, and finished. Renew your 
tubs, and proceed as before. The copperas tub is a half 
a tub of water, with a couple of pail-fulls of copperas 
liquor to set it in the first place ; renewed each time. 

(45.) Slate on Cotton. 

Make up a tub of about 2 of logwood to one of fustic 
liquor, both hot ; enter 3 pieces, give them 5 ends, hedge 
out ; give them 5 ends in copperas liquor ; have it 
stronger or weaker according to shade wanted. This 
finishes them. Renew your tubs, and proceed as before, 

(46.) Purple on Cotton, 

Get up a tub of hot logwood liquor, enter 3 pieces, 
give them 5 ends, hedge out ; enter them into a clean alum 



RECEIPTS ON DYEING. 367 

tub, give them 5 ends, hedge out ; get up another tub of 
logwood liquor, enter, give them 5 ends, hedge out ; re- 
new your alum tub, give them 5 ends in that, and finish. 

(47.) Black on Cotton. 

First take your pieces and boil them in sumach liquor, 
in a large copper vessel, if you have it, that will hold 60 
or 70 pieces, in which you put about a bushel and a 
half of sumach ; let them stay all night if it is conve- 
nient ; take out, and <3nter them into the lime-tub, 3 at 
a time, give them 4 ends, hedge out ; enter them into the 
copperas tub, give them 5 ends, hedge out ; enter them 
into the lime again, give them 4 ends, hedge out ; enter 
them into another tub with tolerably strong logwood 
liquor, give them 5 ends ; put them to one side of the 
tub, put in enough of copperas liquor to blacken them, 
(about a couple of quarts,) then give them a few more 
ends, and they are finished. With this process, it is the 
same as with the greens. After sumaching, liming, cop- 
perassing, and second lining is repeated, till you get as 
many as will answer you to finish that day, the tubs 
being renewed after each 3 pieces : then comes the fin- 
ishing ; after each 3 pieces, the logwood and copperas- 
liquor is thrown away, because the copperas kills the log- 
w^ood, and so renders it unfit for the next pieces. It is 
frequently the case, that instead of the first process of 
sumach boiling, they collect the old sumach, and fustic, 
and logwood liquor, that has no copperas or lime in it, 
into a large tub, and all the pieces that are spoiled in the 
other colours, they throw them into this tub, let them lay 
a few days till they are ready to dye blacks, and this 
answers instead of the sumaching. 

For the foregoing cotton shades, the pieces are first 
taken and boiled in a wood or copper cistern, as circum- 
stances may be, in order to take out the sizing, and pre- 
pare them to receive the dye. 

(48.) To put a fine gloss on Silk. 

Take a fair white potato, cut it in very thin slices, 
pour on it boiling water, let stand till rather cool, take 



368 RECEIPTS ON DYEING. 

out the slices of potato, run your silk through this water, 
squeeze out, smooth while damp, and you will have a 
very superior gloss. I tried this on black silk, and found 
it to answer well. If it should not answer on lighter 
colours, try the following one. If a quantity of silk, of 
course proportion your potatos. 

(49.) Another way. 

Ii^STEAD of a potato, use a small quantity of isinglass, 
dissolved in water. Use it the same as the above in 
every particular, one oz. of isinglass will answer 1 lb. of 
silk. 

(50.) Names of the principal Dyeing Materials. 

Alum, argal, or tartar, green copperas, verdigris, blue 
vitriol, quercitron, and oak bark, mahogany-sawdust, 
with acetate of alumine, mordant forms a good orange 
inclining to flesh colour ; fenugreek, logwood, fustic, Bra- 
zil wood, braziletto, camwood, barwood, and all other 
redwoods, peachwood, sumach, galls, weld, madder of 
various kinds, safllower, savory, green ebony, annatto, 
turmeric, archil, cudbear, cochineal, lac-dye, indigo, and 
tarzabonica or catecheu. This last drug, is now used 
extensively in colour-making and d3'^eing, treated with 
sal ammoniac, pearlash, bicromate of potash, &c. 

(51.) Pearlash mordant, with walnut husks, produces 
a nankeen. 

(52.) JVb. 1, Tin Liquor. 

Take 2 quarts muriatic acid ; killed with 24 oz. of 
granulated tin. This will answer for woollen, or cotton. 

(53.) JVb. 2, Tin Liquor for Yellows on Woollen. 

About 4 parts of muriatic to one of sulphuric, killed 
with granulated tin. This will answer for yellow on 
cotton also. 

(54.) Tin Liquor for Pinks, Scarlets, Crimson, ^c. 
I Of muriatic, 1 of nitric acids, killed with tin. 



RECEIPTS ON DYEING. 369 

(54.) Tin Liquor f for Scarlet, Crimson, ^c. on Silk. 

Take 1 lb. of nitric, and 1 lb. of muriatic acids ; about 
1^ oz. of sal ammoniac ; kill with granulated tin. 

(55.) The manner in which the French Madder is 
marked according to quality. 

First quality marked E. K. F. 2d Quality E. S. F. F. 
3d Quality S, F. F. 4th Quality S. F. 

(56.) To set an Indigo Vat for Cotton. 

Having a sufficiently large vat, nearly fill it with water, 
put in 30 lbs. of ground indigo, 50 lbs. of copperas, 50 
lbs. of slacked lime ; occasionally stir it up for two days. 
When perfectly settled, it is ready for use. When the 
yat is exhausted, renew with 4 lbs, of pearlash, 4 lbs, of 
lime, and 12 lbs. of copperas. 

(57.) A Blue Vat for Silk and Woollen. 

Take 8 lbs. of indigo, about 2 gallons of vinegar, work 
it in the mill till fine ; if this is not convenient put them 
on a slow fire for 24 hours, till dissolved ; put in 1 lb. of 
madder, mix these well, and put them into a vat con- 
taining 100 gallons of urine, stir well twice a day, for 
1 week. It may then be worked, always previously 
stirring it. This vat continues to be good till exhausted. 
Nazarine blues, and deep purples, may be managed with 
this vat and archil dye, taking care to rinse it well from 
one to the other. Archil forms a dye of itself without 
mordant, on silk and w^oollen, when boiled in water. 

(58.) To dye Straivs Red. 

PoiL ground Brazil-wood in a ley of potash, and boil 
your straws in it. 

(59,) Blue on Strata. 

Take a sufficient quantity of potash-ley, 1 lb. of litmus, 
or Ucmus-ground, make a decoction of, and then put in 
the straw, and boil it 



370 RECEIPTS ON DVEilNd. 

(60.) Turkey-red on Leather. 

After the skin has been properly prepared vrilh 
sheep, pig's-dung, &c., then take strong alum-water, and 
sponge over your skin; when dry, boil a strong gall 
liquor, (it cannot be too strong;) then boil a strong Bra- 
zil-wood liquor, the stronger the better ; take a sponge, 
dip it in your liquor, and sponge over your skin ; repeat 
this, till it comes to a full red : to finish your skin, take 
the white of eggs and a little gum-dragon, mix the two 
together in half a gill of water, sponge over your skin, 
and when dry, polish it with a bottle, or piece of glass 
prepared for the purpose. 

(61.) Yellow on Leather. 

Infuse quercitron bark in vinegar, in which boi! a 
little alum, and brush over your skins with the infusion : 
finish same as the red. 

(62.) Another Yellow. 

Take a pint of whiskey, 4 oz. of turmeric ; mix them 
well together; when settled, sponge your skin over, and 
finish it the same way as the red. 

(63.) Blue on Leather. 

For each skin, take 1 oz. of indigo ; put it into boiling 
w^ater, and let it stand one night ; then warm it a little, 
and with a brush, smear the skin twice over, finish same 
as the red. 

(64.) Black on Leather. 

Put your skin on a clean board, sponge it over with 
gall and sumach liquors strong, thf^n take a strong log- 
wood liquor, sponge it over 3 or 4 times ; then take a lit- 
tle copperas, mix it in the logwood liquor, sponge over 
your skin, and finish it sanie as the red, 

{Q^.) Different Shades on Leather. 

The pleasing hues of yellow, brown, or tan colour, are 
readily imparted to leather by the following simple pro- 



RECEIPTS ON DYEING. 371 

cess. Steep saffron in boiling water for a number of 
hours, wet a sponge or soft brush in the liquor, smear the 
leather. The quantity of saffron, as well as of water, 
will of course depend on how much dye may be wanted, 
and their relative proportions on the depth of colour re- 
quired. 

(66.) To dye Leather purple. 

First sponge the leather with alum liquor strong, 
then with logwood liquor strong, or mix them both and 
boil them, and sponge with the liquor : finish same as 
for red. 



INDEX. 



A. 

Acetates Pago 219 

of potass 219 

of ammonia 219 

of lead 220 

of copper 220 

Acetrometer 45 

Acids 156 

Acid, aceric 157 

acetic 157 

amniotic 159 

arsenious 159 

benzoic 158 

butyric 160 

camphoric 161 

carbonic 161 

caseic 163 

chloric 1 63 

chloriodic 164 

chromic 165 

citric 165 

columbic 167 

delphinic 1 67 

elogic 168 

fluoric 168 

-gallic 170 

hydriodic 171 

iodic 171 

laccic 172 

lactic 172 

lithic 173 

malic 1 73 

raargaritic 174 

meconic 175 

melassic 175 

mellitic 175 

menisperraic 177 

molybdic 177 

molybdenous 178 

mucic 178 

muriatic 1 79 

nitric 180 

nitrous 182 

nitro-muriatic 183 

sulphuric 183 

oleic 183 

oxalic 184 

32 



Acid, oxy muriatic 185 

phosphoric 189 

phosphorous 188 

— ' — prassic 188 

pyroligneous 190 

rosacic 193 

rucumic 193 

: sebacic 193 

selinic 194 

sorbic 194 

stanic 196 

suberic 196 

succinic 196 

sulphuric 197 

sulphurous 198 

tartaric 199 

telluric 200 

tungstic 200 

tungstous 201 

zumic 201 

zonic 201 

Adapter 45 

Aerometer 45 

Affinity 18 

Air 18.82 

Alchymy 18 

Alchemist 19 

Alembic 45 

Aluming, for dyeing 354 

Albumen 230. 242 

Alcohol 85 

Alloy 19 

Alkalies 19. 201 

Alkalometer 45 

Almometer 45 

Amber 249 

Ammonia 206 

Analysis, chemical 20 

Annetto on cotton 365 

on silk 365 

Antimony 140 

Animal substances ..... 241 

Annealing of steel and iron . 281 

Apparatus 21 

Arsenic 137 

Assay 21 

Astringent • • 21 

(373) 



374 



INDEX. 



Asphaltum 247 

Astronomy 270 

Atoms 22 

Attraction 23. 310 

B. 

Balsams 233 

Barometer 46 

Basis 2.') 

Bird-lime 232 

Bismuth 135 

Bitumen 247 

Bituminous substances . 247 

Black on silk 356 

on cotton 367 

on thread 363 

on leather 370 

on woollen inclining to 

purple 360 

inclining to brown 360 

jet on woollen 361 

ink 322 

Blacking, to mak^ ......... 328 

Blowpipe 46 

Blood 243 

Blue ink 326 

Prussian, oi^ woollen. . . 361 

on silk .355. 356 

on leather .. ........ . 370 

on straw 369 

vat, on woollen ....... 369 

vitriol 213 

vat, for cotton , 369 

Boots and shoes, to render 

waterproof 337. 339 

Bones : . . 243 

to whiten 350 

to dye and colour 350 

Borates 218 

Bronzing 338 

Brown on woollen 359 

red cast 359 

olive cast 359 

inclining to snufF 360 

on silk 355 

on silk dress 357 

on cotton 366 

Buff on cotton 365 

C. 

Calcareous 26 

Calcination 26 



Caloric .*". 60 

Calorimeter 46 

Candles, imitation of wax . . . 352 
Caoutchouc, or India rubber 

how dissolved . . 338 

its uses ......* 339 

Carburet 26 

Carbon 71 

Carborates 218 

Carbonates 217 

Carbonate of lime 217 

Carbonic oxide . » 226 

Cartilage .... 246 

Caustic 26 

Cawk ,.., 26 

Cementation 26 

Cement, block-cutters 340 

fire and waterproof . 326 

elastic, for belts . . . 344 

— ■ for broken earthen- 
ware 344 

— for cast-iron pipes and 

logs 338.327 

a variety 339 

Central forces 312 

Centre of gravity .' 312 

Cerium 154 

Cloth, to render wind and 

waterproof 343 

Chemical apparatus 59 

nomenclature 11 

terms explained .... 18 

Chlorate 27 

Clock-work 320 

Chromium 152 

Celicium 

Clinometer 46 

Coagulation 27 

Cobalt 147 

Columbium 154 

Colouring matter 232 

Combination 27 

Combustion 27. 255 

Compound 27 

machines 316 

Common salt 215 

slide rule 298 

Concentration 27 

Concretion 27 

Condensation 27 

Copal, to dissolve in alcohol . 329 
in turpentine 329 



INDEX. 



375 



Copal) to dissolve in fixed oil . 331 

Copper 115.283 

Corks for bottles 348 

Crimson on silk 358 

Crane 202 

Crucible 46 

Crystallization 27. 251 

Cupeilatiou 28 

Cucurbits 46 

Cupel 46 

D. 

Decantation 28 

Decoction 28 

Decomposition 28 

Decrepitation 29 

Deflagration 29 

Deliquescence 29 

Deplegmation 29 

Dephlogisticated 29 

Description of the lines of 

the slide-rule 298 

Desiccation 29 

Descensus 29 

Detonation 29 

Digestion 29 

Digester 47 

Distillation 29 

Ductility 29 

Dove on silk 358 

Drab on silk 358 

on woollen 362 

— on cotton 366 

Drunkards, to cure 351 

Dyeing, remarks on 353 

material names of . . 368 

E. 

Ebony, to imitate 349 

Ebullition 30 

Effervescence 30 

EfHorescence 30 

Elastic 30 

Electricity 258 

Eliquation 30 

Equivalents 30 

Essence 30 

Etherial 30 

Ether 87 

Eudiometer 47 



Evaporation 30 

Evaporating vessels 47 

Extract 30 

Extractive matter 231 

F. 

Fermentation 31 

Fibrin 242 

Filteration 31 

Fire and waterproof cement 326 

Fixed 32 

Fluate 32 

Fluates 207 

Flesh colour on silk 358 

Fluate of lime 218 

of silex 218 

Fluid 32 

Flux 32 

Fluxion 32 

Fly wheels » . . . . 317 

Friction 317 

Fulmination 33 

Fusion 33 

Furnace 47 

G. 

Galvanism 261 

Gas 33. 84 

Gasometer 47 

Genometer 48 

Gelatine 230 

Gilding 340 

on calf and sheep-skin 348 

Glauber's salts 211 

Gloss, to put on silk .... 367. 368 

GJue 246. 29G 

method of preparing 

and using 341 

Gluten 230 

Gold 96 

to dye on silver medals 

and lamellas through 

and through 347 

Graver's improved method of 

tempering 346 

Green on silk 355 

on woollen 361 

Greeii on cotton 364 

Green sulphate of iron 212 

Grey on silk 357 



376 



INDEX. 



Gum- Arabic 234 

British 236 

Copal 236 

elastic 237 

lac 237 

Senegal 235 

tragacanth 235 

- — — resins 238 

H. 

Hams, to cure 244 

Honey 232 

Hands, easy method of clean- 
ing 346 

Horn 243 

Horn, to soften 345 

Hydrogen 67 

Hydrometers 48 

Hygrometers 49 

Hypoclepsium 49 

Hyper-oxymuriate of potass . . 216 

I. 

Ide 33 

Inclined plane 315 

Incineration 33 

Inflammable 33 

Infusion 33 

Ink, black 325 

blue 326 

•^ -red 326 

Indian or China 342 

Ink powder 347 

Indigo, sulphate of 355 

vats 369 

lodate 33 

Iodide 33 

Iron, to prevent from rusting 347 

to give a temper to cut 

porphyry 347 

Iron 118.273 

Iridium 155 

Ivory, to sofl;en 349 

dyeing 342. 349 

—. to whiten and polish . . 350 

J. 

Japanning 333 

Japan grounds 334 

— — work polishing 334 



L. 

Lacquer 33 

Lactate 33 

Lead 106.289 

Leather, different shades of 

dyeing 370 

Levigation 34 

Lever 312 

Light 58 

Lilac on woollen 362 

Liquors, scalding and prepar- 
ing for dyers 

Liquefaction 34 

Lixiviation 34 

M. 

Maceration 34 

Madder, French, how marked 

according to quahty 369 

Magistery .... 34 

Magnetism 262 

Manganese 150 

Matter 309 

Maceration 356 

Maroon on silk 365 

Martial 34 

Mechanical exercises 273 

Men and horses, considered as 

first movers 317 

Mechanics 309 

Menstruum 34 

Mercury 100 

Metallic oxides 227 

Metals 88 

Mildew, to remove from linen 344 

Milk 244 

Mill-work 318 

Mineralize . 34 

Motion 311 

Mother-water 34 

Maroon dyeing on silk ..... 356 

Mortar 49 

Mucilage 233 

Muffles 49 

Muriates 215 

of soda 215 

of potass 215 

of ammonia 216 



INDEX. 



377 



N. 

Narcotic principle 231 

Neutral 34 

Neutralization 34 

Nickel 113 

Nitrates 213 

of potass 213 

of soda 214 

of ammonia 215 

Nitrogen 66 

O. 

Of substances 57 

Oil, 1 oz. of which will last as 

long as 1 lb. of any other . . 348 
Oil to prevent smoking in 

lamps 342 

Oil to prevent pictures from 

becoming black 348 

Oil, to extract from any flower 352 

— drying to prepare 336 

Olive on silk 357 

Optics 267 

Orange on cotton 356 

on woollen 363 

Organic substances 228 

Osmium 155 

Oxides 35.223 

Oxidation 35 

Oxygenation 35 

Oxyiode 35 

Oxygen 63 

Oxides of nitrogen 224 

of hydrogen 226 

of sulphur 226 

of phosphorus 226 

P. 

Paint, substitute for 337 

Palladium 104 

Pearl-ash 20S 

Pendulums 321 

Petrifaction 35 

Phlegm 36 

Phlogiston 36 

Phosphorus 76 

Phosphates 36. 221 

of soda 221 

of soda and ammo- 

nia 222, 

32* 



Phosphate of lime 222 

Pink on silk 355 

Pitch 239 

Platina 92 

Pneumatics 264 

Portable balls for taking spots 

out of clothes 342 

Potassium 129 

Potass 203 

Potash 208 

Precipitation 36 

Preparation of dye liquors . . . 354 

Principles 37 

Prussiate of iron 222 

Prussiate of potass and iron . 223 

Pulley 314 

Purple on leather 371 

on cotton 366 

Putrefaction 37 

Pyrites 317 

Pyroligneous tar 239 

Pyrometer 49 

R. 

Radical 37 

Rancidity 37 

Reagent 37 

Rectification 40 

Receiver 53 

Red sulphate of iron ......... 212 

Red ink 326 

Red on cotton 365 

on straw 369 

Turkey on leather 370 

on woollen 362 

Reduction i 41 

Remarks on chemical appa- 
ratus 56 

Repulsion 311 

Residuum 41 

Resins .... 233 

Retorts ,. 53 

Rhodium 146 

Roasting 41 

Rosin, brown and yellow . . . 240 



Sal 42 

Salifiable 42 

Salve, excellent 339 



378 



INDEX. 



Sal ammoniac 216 

Saline 42 

Saline products 202 

Sails 209 

Salt.petre 213 

Saturation 42 

Sediment 42 

Semi 42 

Simple 42 

Silver 109 

Slate on silk 357 

on cotton 366 

on woollen 363 

Silver to write on 351 

Slide rule 204 

Scale 204 

Soda 204 

Soda water, to make 344 

Sodium 132 

Soldering 293 

of ferrules ........ 293 

Solution 43 

Space 310 

Specific gravity 43 

Spirit 43 

Spots, to remove from silk, 

cotton and woollen 343 

Stratification 43 

Starch 229 

Steel, blueing of .' 280 

Stone colour on silk 357 

Sub 43 

Sublimation 44 

Suborate of soda 218 

Sub-carbonate of soda 217 

of potass 217 

Sugar 229 

of lead 220 

Sulphur 70 

Sulphate of alumina 210 

of indigo 355 

~ of alumine and potass 211 

of copper 213 

of soda 211 

Sulphites 213 

Super 44 

Super-tartrate of potass 220 



Table of saline products 



202 



Table of divisions for the slide 

rule 299 

Tantalium 151 

Tanning 231 

Tartrates 220 

of potass and soda . 221 

and anti- 
mony, 221 

Tar 238 

Tellurium 144 

Thermometer 53 

Tin liquor on silk, cotton, and 

wool . . . . c 368, 369 

Tin 122. 286 

Titanium 152 

Tortoise-shell, preparation for 350 

Trituration 44 

Tungsten 145 

U. 

Undulations, to make on wood 349 

Uranium 146 

Ureter 44 

V. 

Viscidity 45 

Varnish from amber 332 

— a variety 329 

copal 329 

for copper-plate prints 332 

to gild with without 

gold 332 

to engrave with aqua- 
fortis 332 

for harness 345 

to fasten the leather 

on top- rollers in fac- 
tories 345 

shell-lac 331 

seed-lac 331 

Vegetables 228 

Vinegar, to increase the 

strength of 351 

Vinegar, to make 351 

portable 352 

Volatilization 45 

W. 

Water 78 

Waters, mineral 80 



INDEX, 



379 



Wax 231 

dry . . . = 45 

humid 45 

Wedge 315 

Wheel-carriages 319 

Wheel and axle 314 

White-wash that will not rub 

off 345 

Wine, to restore that is sour -351 

to correct the bad taste 351 

Woody fibre 232 



Wood, to dye red 348 

to petrify 350 



Yellow on cotton 364 

on leather 370 

on silk 358 

on woollen 363 

Z. 

Zinc 127. 292 



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